Uploaded byalycefeldmanness
11 views

The Discovery of Global Warming Spencer R. Weart

The Discovery of Global Warming Spencer R. Weart The Discovery of Global Warming Spencer R. Weart The Discovery of Global Warming Spencer R. Weart

Download to read offline
The Discovery of Global Warming Spencer R. Weart download pdf https://ebookultra.com/download/the-discovery-of-global-warming-spencer- r-weart/ Discover thousands of ebooks and textbooks at ebookultra.com download your favorites today!
We have selected some products that you may be interested in Click the link to download now or visit ebookultra.com for more options!. Global Warming 1st Edition Natalie Goldstein https://ebookultra.com/download/global-warming-1st-edition-natalie- goldstein/ Role of the Government The Confronting Global Warming 1st Edition Jacqueline Langwith https://ebookultra.com/download/role-of-the-government-the- confronting-global-warming-1st-edition-jacqueline-langwith/ Climate Confusion How Global Warming Hysteria Leads to Bad Science Pandering Politicians and Misguided Policies that Hurt the Poor First Edition Roy Spencer https://ebookultra.com/download/climate-confusion-how-global-warming- hysteria-leads-to-bad-science-pandering-politicians-and-misguided- policies-that-hurt-the-poor-first-edition-roy-spencer/ Global Warming The Complete Briefing 5th Edition John Houghton https://ebookultra.com/download/global-warming-the-complete- briefing-5th-edition-john-houghton/
Global Warming Understanding the Forecast 2nd Edition David Archer https://ebookultra.com/download/global-warming-understanding-the- forecast-2nd-edition-david-archer/ Encyclopaedia of global warming Vol 2 1st ed. Edition Syed https://ebookultra.com/download/encyclopaedia-of-global-warming- vol-2-1st-ed-edition-syed/ Encyclopedia of global warming climate change 2nd edition Edition Philander https://ebookultra.com/download/encyclopedia-of-global-warming- climate-change-2nd-edition-edition-philander/ Global Warming in the 21st Century 1st Edition Juliann M. Cossia https://ebookultra.com/download/global-warming-in-the-21st- century-1st-edition-juliann-m-cossia/ Global Warming and the American Economy A Regional Assessment of Climate Change Robert Mendelsohn https://ebookultra.com/download/global-warming-and-the-american- economy-a-regional-assessment-of-climate-change-robert-mendelsohn/
The Discovery of Global Warming Spencer R. Weart Digital Instant Download Author(s): Spencer R. Weart ISBN(s): 9780674011571, 0674011570 Edition: illustrated edition File Details: PDF, 3.31 MB Year: 2003 Language: english
1 Mason (1957), p. 192. THIS IS THE TEXT OF AN ESSAY IN THE WEB SITE “THE DISCOVERY OF GLOBAL WARMING” BY SPENCER WEART, HTTP://WWW.AIP.ORG/HISTORY/CLIMATE. JUNE 2007 HYPERLINKS WITHIN THAT SITE ARE NOT INCLUDED IN THIS FILE. FOR AN OVERVIEW SEE THE BOOK OF THE SAM E TITLE (HARVARD UNIV. PRESS, 2003). COPYRIGHT © 2003-2007 SPENCER WEART & AMERICAN INSTITUTE OF PHYSICS. Chaos in the Atmosphere Before they could understand how climates change, scientists would have to understand the basic principles for how any complicated system can change. Early studies, using highly simplified models, could see nothing but simple and predictable behavior, either stable or cyclical. But in the 1950s, work with slightly more complex physical and computer models turned up hints that even quite simple systems could lurch in unexpected ways. During the 1960s, computer experts working on weather prediction realized that such surprises were common in systems with realistic feedbacks. The climate system in particular might wobble all on its own without any external push, in a “chaotic” fashion that by its very nature was unforeseeable. By the mid 1970s, most experts found it plausible that at some indeterminate point a small push (such as adding pollution to the atmosphere) could trigger severe climate change. While the largest effects could be predicted, important details might lie forever beyond calculation. Few natural phenomena change so radically and unpredictably as the daily weather. Meteorologists had long understood how the atmosphere in a given locality could be capricious and unstable from hour to hour. As one authority explained in 1957, tiny disturbances in the air, far below the limits of observation, could grow into large weather systems within a few days. Nobody could predict these unstable processes, so “there is an effective time barrier beyond which the detailed prediction of a weather system may well remain impossible.” Beyond that limit, which might be only a few days, one could only look to statistics, the probability of rain or frost in a given month.1 Climate was expected to be steadier. Climate was the statistics, defined as a long-term average. The daily fluctuations, people assumed would cancel one another out over the long run, for the atmospheric system was supposed to be self-stabilizing. True, it was undeniable that even a large system could be unstable. Back around the end of the 19th century, the great French mathematician Henri Poincaré had noted that even the orbit of a planet could depend on some tiny fluctuation, as difficult to predict as whether a ball rolling down a knife-edge would fall to left or right. In the 1920s, quantum physicists showed that a lack of certainty was altogether fundamental. This was Werner Heisenberg’s Uncertainty Principle, made vivid by Erwin Schrödinger’s fable of a cat that might be alive or dead depending on the strictly random decay of a single atom. These ideas worked their way only gradually into common awareness. For decades, scientists who studied complex systems mostly just ignored the ideas. Few questioned that the automatic self-correction of the great natural systems would always keep planets in their accustomed orbits, and that over future decades the rains would fall pretty much as they had in the past.
Weart DGW 6/07 Chaos - 2 1 Russell (1941), p. 91. 2 Landsberg (1941, rev. ed. 1947, 1960), pp. 261-268; he cites Brückner (1890a). Of course, anyone who lived through the harrowing Dust Bowl drought of the 1930s, or heard grandfathers talk about the freezing winters of the 1890s, knew that climate could be seriously different from one decade to the next. Few wanted to explain this as mere random drifting. Surely nature was not altogether capricious? Every change must have its specific explanation. Perhaps, for example, rainfall decreased when soils were dried up by overgrazing, and perhaps cold spells followed an increase in smoke from volcanic eruptions. Even more popular than this idea of particular causes for particular deviations was an assumption that features of nature follow periodic patterns, diverging only to return. Things from tides to rabbit populations go through regular cycles, and it was easy to suppose that climate too was cyclical. The idea fascinated many professional and amateur meteorologists. If you could detect a regular cycle in climate, you could develop a scientific explanation for climate change, and use it to calculate predictions of economic value—and perhaps make a killing on the wheat futures exchange! From the 19th century forward, then, people who liked to play with data labored to extract climate cycles from weather statistics. One or another worker discovered a plausibly regular rise and decline of temperature or of rainfall over months or decades in this region or that. Given enough different bodies of data, people could also turn up correlations between a weather cycle and some other natural ebb and flow, notably the eleven-year cycle of sunspots. A 1941 U.S. Weather Bureau publication noted that some 50 climate cycles had been reported, ranging from days to centuries (not to mention the ice ages, which seemed to come and go regularly over hundreds of thousands of years). “Each man who has proposed one or more of these cycles,” the Bureau remarked, “has become convinced that he has found a particular rhythm.”1 Many meteorologists repudiated the whole enterprise, seeing nothing but random fluctuations from the norm. There remained a good number who believed that cycles were probably there, just at the edge of what the data could prove. An indicator of middle-of-the-road opinion was Helmut Landsberg’s authoritative climatology textbook of 1941. Among other cases, Landsberg described how “widespread attention” had focused upon a cycle of around 33 years in the level of lakes (which gave a good measure of average precipitation). Detected in the 1890s, the cycle had been used to predict how much rain would fall in the late 1920s—but the prediction had failed ignominiously. Nevertheless, Landsberg thought there was a real effect at work, perhaps an irregular rhythm that varied between 30 and 40 years long. “Scientific skepticism is well warranted in the research on climate cycles,” he admitted. “Nevertheless some of them seem to have much more than chance characteristics...”2 Meanwhile the stock of weather observations increased rapidly and calculation techniques improved, so that it became increasingly possible to offer solid proof of whether or not a given cycle was valid. The answers were usually negative. By the middle of the 20th century, opinion among meteorologists was divided about the same way as at the start of the century. Some expected that a few cycles would eventually be pinned
Weart DGW 6/07 Chaos - 3 1 Fultz et al. (1959). 2 Bjerknes (1921). 3 Lorenz (1967), p. 124. 4 Fermi et al. (1965), see introduction by S. Ulam, pp. 977-78; Metropolis (1992), p.129; note also Ulam (1976), pp. 226-28. down, while others believed that no cycles existed—the variations of climate were purely random. Progress was stymied unless clues could be found in some new approach. A big clue came in the 1950s, when a few scientists decided to build actual physical models of climate. Perhaps if they studied how a fluid behaved in a rotating pan, they would learn something general about the behavior of fluid systems like the rotating planet’s atmosphere. These “dishpan” studies turned out to be surprisingly effective in modeling features of the atmosphere like weather fronts. What was most thought-provoking was the way the circulation of a fluid in the laboratory could show different patterns even when the external conditions remained the same. Poke the fluid in the rotating dishpan with a pencil, and you couldn't predict which of two or three possible states the circulation would settle into. The choice of pattern depended in some arbitrary, unpredictable way on the system’s past history.1 Of course, random behavior could be no surprise to anyone who watched the tumbling of fluids. When water flows through a channel, if the speed gradually increases, at some point the smooth, steady flow gives way to a turbulent flow with vortexes swirling unpredictably. In 1921, Vilhelm Bjerknes had suggested that a similar instability might be at the root of major daily disturbances of the atmosphere. Beyond some critical point, the symmetric flow of wind would become unstable and spin off storms.2 In 1956, Edward Lorenz proposed an explanation along those lines for the dishpan experiments. As the dishpan experiments were refined, however, they seemed to point to something much more unfamiliar.3 A second essential clue came from another new field, digital computation. As scientists applied computers to a variety of tasks, oddities kept popping up. An important example came in 1953 when a group at Los Alamos, led by the great physicist Enrico Fermi, used the pioneer computer MANIAC to study how a complex mechanical system behaved. They wrote equations that described a large number of “nonlinear” oscillators (the mathematical equivalent of springs with flaws that kept them from stretching smoothly), all coupled to one another. Physical intuition insisted that the distribution of energy among the oscillators in such a system should eventually settle down into a steady state, as a shaken glass of water will gradually come to rest. That was indeed what Fermi’s group saw, after the computer had ground away at the numbers for a while. Then one day, by accident, they left the computer running long after the steady state had been reached. Fermi’s group was amazed to find that the system had only lingered for a while in its steady state. Then it reassembled itself back into something resembling the initial distribution of energy. Like the flow in the rotating dishpan, the system had at least two states that it could flip between for no obvious reason. Further computer experiments showed that the system shifted unpredictably among several “quasi-states.”4 In retrospect, this was the first true computer
Weart DGW 6/07 Chaos - 4 1 The authors called these “ergodic” fluctuations. Eriksson and Welander (1956), see p. 168. 2 Richardson (1922); Rossby (1959), p. 30 [this is a translation of Rossby (1956)]; recent analysis shows that Richardson’s primitive computation could have succeeded fairly well if he had started with perfect data. But his process of computation with a large time-step grossly experiment, with an outcome that foreshadowed much that came later. The lesson, scarcely recognized at the time, was that complex systems did not necessarily settle down into a calm stable state, but could organize themselves in surprising large-scale ways. Fermi’s group described these wholly unexpected results at a few meetings during the 1950s, stirring curiosity among physicists and mathematicians. Meanwhile there were hints that such behavior was not confined to abstract mathematical systems. For example, a pair of scientists wrote a simple system of equations for the exchanges of carbon dioxide gas among the Earth’s atmosphere, oceans, and biosphere, and ran the equations through a computer. The computations tended to run away into self-sustaining oscillations. In the real world that would mean climate instability—or even fluctuations with no regularities at all.1 Nothing specific came of these and other peculiar results. It is not uncommon for scientists to turn up mildly anomalous calculations. They stick them away in the back of their minds until someone can explain what, if anything, it all has to do with the real world. The more people worked with computers, the more examples they found of oddly unstable results. Start two computations with exactly the same initial conditions, and they must always come to precisely the same conclusion. But make the slightest change in the fifth decimal place of some initial number, and as the machine cycled through thousands of arithmetic operations the difference might grow and grow, in the end giving a seriously different result. Of course people had long understood that a pencil balanced on its point could fall left or right depending on the tiniest difference in initial conditions, to say nothing of the quantum uncertainties. Scientists had always supposed that this kind of situation only arose under radically simplified circumstances, far from the stable balance of real-world systems like global climate. It was not until the 1950s, when people got digital machines that could do many series of huge computations, that a few began to wonder whether their surprising sensitivity pointed to some fundamental difficulty. At first the problem had seemed simply a matter of starting off with the right equations and numbers. That caught attention as early as 1922, when Lewis Fry Richardson published the results of a heroic attempt to compute by hand how a weather pattern developed over eight hours. His starting point was an observed pattern of winds and barometric pressure. Numerically simulating a day of development, Richardson’s numbers had veered off into something utterly unlike real weather. He thought his calculation would have worked out if only he could have begun with more accurate wind data. But as the meteorologist Carl-Gustav Rossby pointed out in 1956, people routinely made decent 24-hour predictions by looking at weather maps drawn from very primitive data. “The reasons for the failure of Richardson’s prognosis,” the puzzled Rossby concluded, “must therefore be more fundamental.”2
Weart DGW 6/07 Chaos - 5 magnified the wind data errors, which a human forecaster would have intuitively adjusted in gazing at the map. Worse, the process amplified the random sound waves that show up in the complete solution of equations for a fluid. See discussion by Lorenz (1967), p. 131; Norton and Suppe (2001), p. 93; for modern recalculation by P. Lynch, see Hayes (2001). 1 Levenson (1989), p. 89. 2 Norman Phillips, interview by T. Hollingsworth, W. Washington, J. Tribbia and A. Kasahara, Oct. 1989, p. 40, copies at National Center for Atmospheric Research, Boulder, CO, and AIP.. 3 C.E.P. Brooks quoted by Engel (1953); Nebeker (1995), p. 189. 4 Wexler (1956), p. 480. 5 Sutcliffe (1963), pp. 278-79. Instead of “external” he speaks of “extraneous” causes. The question of unstable computations was addressed most persistently by Philip Thompson, who had taken up weather prediction with the pioneering ENIAC computer group. In 1956, Thompson estimated that because of the way small irregularities got magnified as a computation went forward, it would never be possible to compute an accurate prediction of weather more than about two weeks ahead.1 Most scientists felt that all this resulted from the way computers chopped up reality into a simplified grid (and in fact some clever changes in the mathematics stabilized Phillips’s model). As another computer pioneer remarked, “meteorologists get so used to the idea that something bad is going to go wrong with their forecast that you’re not surprised” if a calculation couldn’t be made to work.2 The real world itself was presumably not so arbitrary. There had long been a few meteorologists, however, who felt that the atmosphere was so “delicately balanced” that a relatively minor perturbation could trigger not just a week’s storm, but a large and durable shift.3 In the 1950s, the idea was developed in speculative models of climate that showed abrupt variations, due to self-sustaining feedbacks involving factors such as snow cover. Support came from new data which suggested that climate conditions in the past had sometimes in reality jumped quite rapidly into a different state. The respected U.S. Weather Bureau leader, Harry Wexler, warned that “the human race is poised precariously on a thin climatic knife-edge.” If the global warming trend that seemed to be underway continued, it might trigger changes with “a crucial influence on the future of the human race.”4 The intellectual basis of the new viewpoint was well expressed in 1961 by R.C. Sutcliffe at an international climate conference. Using the popular new language of cybernetics, he described climate as a complex nonlinear feedback system. Unceasing variation might be “built-in,” an intrinsic feature of the climate system. Thus it might be pointless to look for external causes of climate change, such as solar variations or volcanic eruptions. Every season the pattern of the general circulation of the atmosphere was newly created, perhaps in a quite arbitrary way. The “sudden jumps” seen in the climate record, Sutcliffe concluded, are “suggestive of a system controlling its own evolution.”5 The father of cybernetics himself, mathematician Norbert Wiener, insisted that attempts to model the weather by crunching physics equations with computers, as if meteorology were an exact
Weart DGW 6/07 Chaos - 6 1 “self-amplification”: Wiener (1956a), p. 247, also warning that observations were “a very sketchy sampling of the true data.”; by “misleading” Wiener meant von Neumann and Charney. Jule Charney and Walter Munk, “Early History of Computing in Meteorology,” unpublished, copy from Arakawa’s papers kindly furnished by Paul Edwards, p. 9. See also Cressman (1996), p. 31. 2 “Dialogue between Phil Thompson and Ed Lorenz,” 31 July 1986, copies at National Center for Atmospheric Research, Boulder, CO,; Gleick (1987) 1295, pp. 11-18. science like astronomy, were doomed to fail. Quoting the old nursery rhyme that told how a kingdom was lost “for want of a nail” (which caused the loss of a horseshoe that kept a knight out of a crucial battle), Wiener warned that “the self-amplification of small details” would foil any attempt to predict weather. One pioneer in computer prediction recalled that Wiener went so far as to say privately that leaders of the work were “misleading the public by pretending that the atmosphere was predictable.”1 In 1961, an accident cast new light on the question. Luck in science comes to those in the right place and time with the right set of mind, and that was where Edward Lorenz stood. He was at the Massachusetts Institute of Technology, where development of computer models was in the air, and intellectually he was one of a new breed of professionals who were combining meteorology with mathematics. Lorenz had devised a simple computer model that produced impressive simulacra of weather patterns. One day he decided to repeat a computation in order to run it longer from a particular point. His computer worked things out to six decimal places, but to get a compact printout he had truncated the numbers, printing out only the first three digits. Lorenz entered these digits back into his computer. After a simulated month or so, the weather pattern diverged from the original result. A difference in the fourth decimal place was amplified in the thousands of arithmetic operations, spreading through the computation to bring a totally new outcome. “It was possible to plug the uncertainty into an actual equation,” Lorenz later recalled, “and watch the things grow, step by step.” Lorenz was astonished. While the problem of sensitivity to initial numbers was well known in abstract mathematics, and computer experts were familiar with the dangers of truncating numbers, he had expected his system to behave like real weather. The truncation errors in the fourth decimal place were tiny compared with any of a hundred minor factors that might nudge the temperature or wind speed from minute to minute. Lorenz had assumed that such variations could lead only to slightly different solutions for the equations, “recognizable as the same solution a month or a year afterwards... and it turned out to be quite different from this.” Storms appeared or disappeared from the weather forecasts as if by chance.2 Lorenz did not shove this into the back of his mind, but launched himself into a deep and original analysis. In 1963 he published a landmark investigation of the type of equations that might be
Weart DGW 6/07 Chaos - 7 1 Lorenz (1963), pp. 130, 141. This paper, now considered a classic, was not noticed by mathematicians for nearly a decade; like nearly all the stories in these essays, there is a lot more to this one, especially work by a number of other mathematicians. For additional details, see Dalmedico (2001). 2 His term for arbitrary was “aperiodic.” Lorenz (1964); Gleick (1987), pp. 21-31, 168- 169. 3 Lorenz (1968), quote p. 3; he described the randomness of a system of 26 equations (which was not very many for meteorology), published in Lorenz (1965); see also Kraus and Lorenz (1966); Lorenz (1970). 4 Mitchell said his printed “Concluding Remarks” were based on Roger Revelle’s summary at the conference itself. Mitchell (1968), pp. 157-58. used to predict daily weather. “All the solutions are found to be unstable,” he concluded. Therefore, “precise very-long-range forecasting would seem to be non-existent.”1 That did not necessarily apply to the climate system, which averaged over many states of weather. So Lorenz next constructed a simulacrum of climate in a simple mathematical model with some feedbacks, and ran it repeatedly through a computer with minor changes in the initial conditions. His initial plan was simply to compile statistics for the various ways his model climate diverged from its normal state. He wanted to check the validity of the procedures some meteorologists were promoting for long-range “statistical forecasting,” along the lines of the traditional idea that climate was an average over temporary variations. But he could not find any valid way to statistically combine the different computer results to predict a future state. It was impossible to prove that a “climate” existed at all, in the traditional sense of a stable long-term average. Like the fluid circulation in some of the dishpan experiments, it seemed that climate could shift in a completely arbitrary way.2 These ideas spread among climate scientists, especially at a landmark conference on “Causes of Climate Change” held in Boulder, Colorado in August 1965. Lorenz, invited to give the opening address, explained that the slightest change of initial conditions might randomly bring a huge change in the future climate. “Climate may or may not be deterministic,” he concluded. “We shall probably never know for sure.”3 Other meteorologists at the conference pored over new evidence that almost trivial astronomical shifts of the Earth’s orbit might have “triggered” past ice ages. Summing up a consensus at the end of the conference, leaders of the field agreed that minor and transitory changes in the past “may have sufficed to ‘flip’ the atmospheric circulation from one state to another.”4 These concerns were timely. Around the mid 1960s, many people were starting to worry about environmental change in general as something that could come arbitrarily and even catastrophically. This was connected with a growing recognition, in many fields of science and in the public mind as well, that the planet’s environment was a hugely complicated structure with points of vulnerability. Almost anything might be acutely sensitive to changes in anything else. So it was hopeless to look for comfortably regular weather cycles driven by single causes. The
Weart DGW 6/07 Chaos - 8 1 Wilson and Matthews (1971), p. 109. 2 Stringer (1972), pp. 300, 307-08; Federal Council for Science and Technology (1974); this is included as an appendix in United States Congress (95:1) (1977), p. iii; another review accepting continual and unpredictable change was Kutzbach (1976), p. 475. 3 In sum, “numerically small changes in climatic variables may produce significant environment changes,” Bryson (1974), pp. 753, 756, 759. 4 E.g., Newell (1974). 5 Lorenz (1970); as cited by Sellers (1973), p. 253. 6 GARP (1975), pp. 32-33. many forces that acted upon climate, all interacting with one another, added up to a system with an intrinsic tendency to vary, hard to distinguish from random fluctuation. A tentative endorsement of Lorenz’s ideas came in a comprehensive 1971 review of climate change. While the authors did not feel Lorenz had proved his case for certain, they found it “conceivable” that sensitivity to initial conditions “could be a ‘cause’ of climate change.”1 A typical textbook of the time spoke of the atmosphere as an overwhelmingly complex system of different “types of circulation” with rapid transitions among them. “The restlessness of the atmosphere sets a theoretical limit to its predictability,” the author concluded. That not only ruined any hope of forecasting weather beyond a week or so, but similarly hampered our ability to foresee climate change. A high-level panel on climate change agreed in 1974 that “we may very well discover that the behavior of the system is not inherently predictable.”2 In the early 1970s, concern about arbitrary climate change was redoubled by news reports of devastation from droughts in Africa and elsewhere. The most dramatic studies and warnings came from meteorologist Reid Bryson, who pointed out that the African drought had “minuscule causes,” which “suggests that our climate pattern is fragile rather than robust.”3 Meanwhile speculative new models suggested that a slight variation of external conditions could push the climate over an edge, plunging us from the current warmth into an ice age.4 Studies of dramatic past climate events added plausibility to these models. It was a short step to imagining a system so precariously balanced that it would go through self-sustaining fluctuations without any external trigger at all. As an author of one of the simple models put it, the results raised “the disturbing thought” that science could do no more than follow the history of climate as it evolved.5 Many meteorologists rejected this approach, what one prestigious panel called “the pessimistic null hypothesis that nothing is predictable.” After all, the entire program of the postwar physics- based revolution in meteorology aimed at prediction. Scientists holding to this ideal expected that gross changes could in principle be predicted, although perhaps not their timing and details.6 The task now was to determine where the limits of predictability lay. Theorists worked out mathematical arguments that showed how changes in climate could resemble a “random walk.” Perhaps the atmosphere was staggering like a drunkard among a multitude of possible states. Enough steps this way and that could add up to a large excursion, but in a random direction. If
Weart DGW 6/07 Chaos - 9 1 Hasselmann (1976). 2 Hays et al. (1976). 3 “orbital variations control the timing but not the amplitude.” Hays, Imbrie and Shackleton, reply to Evans and Freeland (1977), p. 530. 4 “stochastic” or “probabilistic” variability Mitchell (1976), p. 481. 5 Lorenz (1993), p. 120. 6 “Predictability: Does the flap of a butterfly’s wings...” was the title of an address by Lorenz to the American Association for the Advancement of Science, Washington, DC, Dec. 29, this picture was valid, then the places the drunken climate reached would be halfway predictable but never entirely so.1 The real world did follow a halfway predictable path, according to one interpretation of new field studies. In 1976, analysis of deep-sea cores revealed a prominent 100,000-year cycle in the ebb and flow of ice ages. That corresponded to a predictable astronomical cycle of variations in the Earth’s orbit. However, the cyclical changes of sunlight reaching the Earth seemed trivially small. The group of scientists who published the evidence thought the cycle of glacial periods must be almost self-sustaining, and the orbital changes only nudged it into the shifts between states.2 They called the variations in the Earth’s orbit the “pacemaker of the ice ages.” In other words, the astronomical cycle triggered the timing of the advance and retreat of ice sheets but was not itself the driving force.3 Without the timing set by this external stimulus, the ice cycles might wander without any pattern at all. Or changes could be set off arbitrarily with a nudge from any of various other forces that were easily as strong as the slight deviations of sunlight. Indeed the record showed, in addition to the main cycles, a great many fluctuations that looked entirely random and unrelated to orbital variations. Meanwhile, computer weather modelers were starting to admit they could find no way to circumvent Lorenz’s randomness. The new viewpoint was captured in a fine review by the leading meteorologist J. Murray Mitchell. He pointed out that climate is variable on all time-scales from days to millions of years. There were naturally many theories trying to explain this multifarious system, he said, and almost any given theory might partly explain some aspect. “It is likely that no one process will be found adequate to account for all the variability that is observed on any given time scale of variation.” Furthermore, the sheer randomness of things set a limit on how accurately scientists could predict future changes.4 Similar ideas were gradually becoming known to the entire scientific community and beyond under a new name—“chaos theory.”5 The magnification of tiny initial variations, and the unpredictable fluctuation among a few relatively stable states, were found to matter in many fields besides meteorology. Most people eventually heard some version of the question Lorenz asked at a 1979 meeting, “Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?” (Already in 1975 a science journalist had asked, “can I start an ice age by waving my arm?”) Lorenz’s answer—perhaps yes—became part of the common understanding of educated people.6
Random documents with unrelated content Scribd suggests to you:
chemicals kept the air purified, and earphones made communication possible. "Stand by for a landing!" Ripon's voice buzzed in the ear phones as Larry reported all hands ready. "We're going down!" The Sky Maid went down in a series of jerky drops. With eventual refinement, a ship equipped with the Ripon Magnetic Control would probably be able to come down as gently as a falling leaf, but this first apparatus was crude and experimental. Just at the end one of Ripon's elbows touched the wrong switch. The rocky surface swept up to meet them at high speed. He shouted hoarsely and spun compensating dials, but before he could check the momentum they struck with a heavy crash. The ship heeled over, and all the lights went out. As Larry was flung off his feet he heard a sharp hiss of escaping air. Momentarily half stunned, Larry lay on the floor in a corner of the control room with the body of another of the crew across his legs. Then he saw a bulky, space-suited figure heave to its feet across the room and heard Ripon's voice in his ear phones. "Leaping ray-blasts, what a crash! But I seem to be alive and in one piece. How about the rest of you?" Other men struggled to their feet and answered their names. One had his helmet smashed and was already dead in the airless atmosphere that remained after the air had rushed out through the shattered wall of the control room, but the rest had nothing more serious than a few bruises. "Well," Colton said. "Here we are! And here we're likely to stay." "It may not be that serious. The first thing is to take stock of our damage."
The Sky Maid, they found on making a complete survey, was far less seriously damaged than might have been the case. The wall of the control room was punctured by a jagged splinter of rock, but there were only a few other minor leaks. Many of the compartments had retained their air. Once the hole was patched and the other leaks stopped, their reserve tanks still held enough air to let them make a homeward voyage in safety. The network of wires outside the hull would require considerable reconditioning, but none of the internal magnetic equipment was ruined. "About five days' work!" Ripon summed up. "And it's primarily a job for the engine room force. Gibson, Colton, the two quartermasters and I will go ashore with several days' supply of chemical capsules for the air conditioners on our helmets. Chief Engineer Masterson remains in command of the ship. Get her back in navigating shape as soon as you can, Chief." Masterson, a grimy and bullet-headed little man with a drooping mustache and something of the look of a mournful Airedale, slapped the side of his duro-glass helmet in a casual salute. Larry knew that the ship was being left in good hands. He had come to have considerable respect for the taciturn engineer. He did not know why Masterson was on board the Sky Maid, very likely because he had been in some trouble similar to Larry's own, but he was certainly an efficient engineer. He wished he felt as sure of the three men who were going ashore with Ripon and himself. Colton he considered thoroughly untrustworthy, and the two quartermasters were a pair of sullen derelicts of the sort that Ripon had picked up off the beach for most of the crew. "Landing party ashore!" Ripon snapped. "Let's get going! This isn't an ordinary exploring party, and every hour counts." VII
They stood on a bare expanse of pitted rock. The Sky Maid had crashed on the outer slope of one of the craters, and the ground rose steadily to the jagged rim of the rocky bowl. Other bare peaks were all about them, black teeth against the starry sky. The earth gleamed large and pale above them. The scene was bleak and silent, unutterably desolate and forlorn, and the little group of Earthlings drew closer together. Then Ripon pointed up the ridge. "We'll go up there and look around. Larry—you carry the radium detector. We mustn't let the exploring fever make us forget our main purpose in having come here." They toiled slowly up the slope. Walking was difficult. Due to the power of their Earthly muscles on this planet of so much lighter gravity, they had a tendency to bound into the air at each step in spite of the heavy leaden soles on the feet of the space suits. Gradually they learned the necessary muscular control, a sort of sliding step, and then they made better progress. Ripon was some yards in the lead as they reached the rim of the crater. For a moment the tall scientist was silhouetted against the stars, then he abruptly dropped flat on the rock and motioned back to them to do the same. His voice was a faint whisper in the ear phones. "Crawl up here slowly, one at a time. Careful!" Larry was the first to join him, lying flat on the rock at Ripon's side. Together they peered down into the crater. It's flat floor was swarming with some sort of queer animal! This particular crater was a small one, and the level floor was only some thirty yards below the rim. Larry stared in amazement at the creatures who were coming to sit in long rows around a small mound in the center of the crater. He hardly knew whether to call them men or animals. They had the hard shell and articulated legs of an insect, but their faces had a semi-human appearance in spite of the pair of long antennae that grew out of their foreheads. Their feet made a dry rustling sound as they clambered down over the
rock, and they carried metal clubs with spiked heads. Larry saw that they walked with four of their six limbs while the upper pair were equipped with three curved fingers each. On the top of each antenna was a round ball that glowed with a phosphorescent light. "I thought there wasn't any life on the Moon!" Larry whispered. Ripon grinned at him through the duro-glass of his helmet. "You thought a lot of things that were wrong, young feller!" It was a weird scene in the cold pale light of the Earth. Some of the insect men came out of small, dome-shaped mounds that might have been houses. Others came climbing down the far side of the crater. Their glowing antennae bobbed in ceaseless motion, and there was a constant dry clicking. Suddenly Larry realized that the creatures were talking together! That meant that there was at least some atmosphere on the Moon! Enough to carry sound! Perhaps it had a different composition than the atmosphere of the Earth. It was certainly very thin, for the air in the control room had instantly escaped through the shattered side and the man with the broken helmet had smothered, but there was enough here to sustain these odd creatures. Then Ripon touched him on the arm, and Larry saw something that a group of the insect- men were very ceremoniously carrying to the mound in the center of the crater. It was an ordinary metal chair of a very common and familiar Earthly pattern, the sort of chair to be found in the cabins and mess rooms of any stratholiner. "One of those old ships must have reached the Moon after all!" Larry whispered. "That chair must be from the wreckage." "Heaven help the survivors if those many-legged devils got hold of them!" "They can't be very strong, with the Moon's gravity so slight," Larry said. "That doesn't prove a thing. They can be light in frame and still very strong. Think how many times his own weight our ant can carry, or
how far a flea can jump." The chair had been placed in the center of the mound, and the Insect-men drew back. Now thin jets of steam or mist began to pour up around the mound, forming a foggy curtain that hid it. The mist only rose a little way, then dropped slowly down again to form an icy film on the cold rocks. The jets ceased, and mist vanished, and Larry Gibson stared in open-mouthed amazement. A dark-haired girl was standing erect on the crest of the mound! VIII The girl was white-skinned and lovely, utterly different from the grotesque creatures who surrounded her. Larry was crouching near enough to see her faintly smiling eyes, and the curve of her red lips, and the dark hair that fell to her waist behind. Except for the grotesque metallic helmet on her head, and the fact that she wore no clothing except for a silver loin cloth, she might have been a girl of the sort to be seen along the elevated cross-walks of New York City. "Do you see her too?" Ripon whispered. "I do." "We can't both be that crazy, so she must really be there. But how she breathes in that atmosphere, and how she avoids freezing to death, is more than I can tell you." The ceremony had evidently some sort of a religious significance, for the Insect-men were clicking rhythmically and were bowing down before the dark-haired girl. Goddess of the Moon! The girl's head- dress was a grotesque representation of an insect, set with jewels. At the tops of the flexible antennae were a pair of giant rubies. "Boy! Wouldn't I like to get my hands on those stones!" Colton whispered from where he crouched on Ripon's left.
Then Larry noticed something else! A group of perhaps a hundred of the Insect-men were moving swiftly forward between the ranks of their bowing comrades. This group carried shields as well as clubs, and they had the purposeful air of men with a grim and serious errand to perform. The girl was staring over the heads of the crowd with a distant and goddess-like manner, and did not notice the newcomers till they had almost reached her. Then her eyes widened in alarm. She leaped up from her throne and burst into a torrent of shrill clicking. In an instant the crater was in a turmoil. The group of the heavily armed Insect-men charged straight for the mound in the center. Others flung themselves in their path, rallying to the defense of the Goddess. There was a wild flurry of swinging clubs. The spiked heads clanged on metal shields, or cracked sharply on the brittle brown shells of the Insect-men. The significance of the scene before him was still obscure to Larry, but it was evident that some kind of a revolt had broken out. The rebels among the Insect-men were outnumbered, but their metal shields gave them a big advantage and they were better organized. Like a spear-point they drove straight through the confused mass of worshipers and surrounded the low knoll in the center. They brushed its defenders aside and swarmed up toward the dark-haired Goddess. Larry had already drawn his ray-gun, but Ripon was the first to leap to his feet. "Come on, young feller!" he roared. "That girl is the first human thing we've seen on the Moon. We can't let her down. Let's show those many-legged devils how an Earth man can fight!" Larry and Ripon went down the slope of the crater in a series of bounding leaps. The milling Insect-men opened before them, seeming to welcome these unexpected reinforcements. Some of the rebels had already forced the struggling girl to her knees and were lashing her hands behind her back. A solid rank of them faced about with their round shields locked and a tossing fringe of spiked clubs waving atop the metal wall.
The two Earthlings dove for the shield-wall with their guns flashing. Larry ducked as one of the Insect-men hurled a club which just missed his glass helmet, then pressed the trigger of his ray-gun. The murky beam of the rays stabbed into the shield, melted a hole through it in a fraction of a second, and struck down the man behind. The flashing ray-guns of the two adventurers ripped the shield-wall asunder. A wave of the loyal Insect-men poured in behind them. Larry shifted his ray-gun to his left hand, and snatched up a fallen club with his right. It was heavier than he had expected, a well balanced and efficient weapon. The hard brown shells of the rebels cracked like china under the smashing blows of his Earthly muscles. Then he bounded up on the mound and struck down the pair of rebels who held the girl. Her wrists were now tied behind her. Throwing an arm about the girl's shoulders, Larry hastily faced about. Ripon was a few yards away. A ring of his slain lay around him, but his weapons had been knocked from his hands and he was struggling in the grip of a pair of the Insect-men. A third of the creatures was swinging a club to strike a blow at the scientist's glass helmet. Larry instantly fired, the beam of the ray striking the arm that held the club and shearing it clean off at the shoulder. A viscous yellow liquid dripped out, and the creature dropped writhing on the rock while it clicked in pain. Then Colton and the two quartermasters came charging belatedly up, and the fight was over. The crater was dotted with the still forms of dead Insect-men. Larry noticed that their hard shells gleamed dully in the dim light. The surviving rebels had fled off across the far rim of the crater, and the rest of the throng had gone chasing after them. No one remained in the crater except the strange girl and the party from the Sky Maid. When Larry had freed the girl's hands, she turned to the five Earth- men and touched her forehead in a gesture of thanks. Then she stepped across to touch some hidden spring on the far side of the
mound, and a trap door opened in what had apparently been solid rock. The girl led the way down a narrow flight of stairs, motioning for the last man down to pull the trap closed behind them. They stood in a small chamber that had walls of roughly smoothed rock. It was evidently the work of men, for tool marks showed here and there. It was lighted by a green globe set in one wall. The globe appeared to be made of some kind of flexible glass, and it glowed with a faint greenish radiance that overcame the darkness enough to give the place a dim and eerie light. At one side of the room was an oval hole like a slanting well cut in the floor. Beside it stood a pile of low, flat carts. They were about two feet wide by four feet long, and they were supported on axles bearing small wheels the diameter of a man's hand. The girl spoke to Larry twice, first in the clicking talk of the Insect- men and then in some soft and musical tongue that was unlike anything Larry had ever heard. Both times he shook his head. Motioning for them to follow her, she put one of the low carts down near the rim of the hole and sat on it. Then she gave a push with her hands—and vanished. "Come on," Larry said, raking another of the carts. Colton stared at him. "Down that hole?" he asked. "Why not? We've got to find out what all this is about." A second later Larry Gibson found himself shooting down into the interior of the Moon by means of a sloping tunnel cut in the rock. A series of the greenish globes were set in the ceiling at intervals to give the rocky shaft a dim light. The wheels of the cart ran in two grooves cut in the floor, and he shot swiftly downward with a dull humming sound.
Larry was trying to estimate the speed of his downward movement. It was not so terribly fast, probably not really as fast as the nearness of the walls made it appear while they flashed by on either hand. The slope was a gentle one. Although he had gathered considerable momentum, he had no feeling of the car being out of control. As the minutes passed, Larry saw something else. The moisture that had been on the outside of his space suit from the air within the Sky Maid had frozen into a white frost a few seconds after the breaking of the control room wall let the outer cold into the ship. Now the frost was melting! They were getting into warmer regions as they went down. Perhaps they were also running into a heavier atmosphere! Larry held his hand up before him, and had a distinct feeling of pressure against it from the rush of air sweeping up to meet him. A minute later he had tested the atmosphere with the portable oxygen-gauge carried in the equipment pocket of any space suit. Then he took off his helmet. The air was quite warm, and though still very thin it was definitely breathable. Its clean, earthy odor was a pleasant contrast to the chemical product used over and over again inside the helmet of a space suit. A moment later he saw a brighter light ahead and realized that he had come to the bottom of the long shaft. They were in a square room whose walls were of polished gray stone. As Larry got up from his cart and moved in aside from the landing platform, the girl gave him a friendly smile. She had already taken off her ornately jeweled head-dress and placed it in a metal cabinet fastened to the wall. Completely without embarrassment, she tied a strip of gayly colored silk across her bare breasts. Then she tossed her long hair back from her forehead and bound another strip of silk to keep it in place. "That was quite a ride," Larry said. He had spoken in English, knowing that the girl would not understand but hoping the sound of the words would convey a generally friendly impression. She stared at him in startled surprise for a second.
"It is much pleasanter than the upward trip," she said at last. "But—but you spoke in English!" Larry gasped. "Why shouldn't I? My father is a man from Earth. I am Diana Staunton." IX As the others came sliding down into the room, Larry gave each one a formal introduction to Diana. The glow in the girl's eyes showed that she enjoyed their utter amazement. For a girl who had been born on the Moon, even though of Earthly parents, Diana Staunton had a great deal of poise and self-possession. "I am only a Goddess to the sluggish minds of the Insect-men," she explained in answer to Ripon's question. "To our own people of the Lost Caverns I am simply the daughter of one of the nobles." "I knew your father thirty years ago," Ripon said. "He has always told me that other men from Earth would come some day." "Your father can tell me most of the things I want to know, but I am wondering how you managed to survive up there on the surface where there is little or no air and it is always so cold." "I could not stay very long." From a fold in her loin cloth the girl drew out a tightly closed glass bottle that held some white tablets. "These contain oxygen mixed with some gases unknown on Earth, the whole very strongly compressed into solid form. Ten minutes after I swallow one, it is safe for me to go out on the surface. The effect lasts for about fifteen minutes." "Pretty risky if anything delays you," Larry said. Diana shrugged, and her blue eyes grew somber.
"Someone has to do it. The loyalty of the Insect-men is our greatest protection against the evil Lords of Gral-Thala. This is the first time there has ever been anything like a revolt among the Insect-men. I do not know what lies behind it, but it probably means trouble for us of the Lost Caverns." Colton was the last to come down the rocky shaft. Larry noticed that the second officer was ill at ease, disinclined to meet his eyes, and wondered if Colton was ashamed of either his late entry into the fight or his fear of coming down into the Moon's interior. Hardly likely! From what he knew of Gerald Colton, the man was not likely to be ashamed of anything he did. They went through a maze of gray walled passages, still trending downward. Once or twice Larry thought he heard stealthy footsteps behind them, but there was no one in sight when he looked back. On several occasions they passed sentries wearing a makeshift armor, who saluted Diana with long bladed swords. Sometimes they spoke to her in English with a peculiar soft accent, sometimes in that strange tongue that Diana had first used. Larry noticed that these Lunarians looked only slightly different from the peoples of Earth. They had larger eyes, and a greater delicacy of feature. The principle distinguishing feature was their very thin legs. Often they had wide shoulders and deep chests, but since they did not need strong supporting muscles in view of the Moon's slight gravity their legs were thin and narrow. The sentries stared curiously at the Earth-men in their bulky space suits, but the fact that the newcomers were with Diana Staunton seemed to be sufficient passport. They began to pass a greater number of people in the corridors, and finally they stepped through a heavily guarded gate and came to a vast cavern. The place was huge, extending for a good mile ahead of them and with a lofty roof lost in the shadows overhead. Some of the gigantic columns that supported the roof were made of heavy stone blocks. Others were natural rock that had been smoothed and polished. All
over the floor of the cavern were narrow streets, and small cottages built of some queer composition that came in a rainbow of different colors, and little patches of some sort of green grass. A golden and rather misty light pervaded the whole cavern. Square shafts of a brighter radiance darted down from above at irregular intervals, and wherever one of them struck the floor of the cavern there was a small patch of cultivated ground with long-leafed plants. "Agriculture by chemical control!" Ripon whispered in Larry's ear. Diana glanced back at them over her shoulder. "This is Chotan, largest of the Lost Caverns," she said. "The Council of Elders is now in session, and it will be best that we go direct to them." "Why do you call these the Lost Caverns?" Larry asked. "Because we who live here are outlaws, and the location of these vast caves is not known to the Lords of Gral-Thala who rule the other side of the Moon." "Apparently not all the inhabitants of the Moon are so friendly," Ripon said. "If you came into the hands of the Lords of Gral-Thala," she said grimly, "they would tear the skin from your bodies and use it to lace their scented golden boots!" Large-eyed Lunarians stared curiously at the Earth-men as they hurried through the streets of the underground village. Diana led them direct to a broad-beamed, red-roofed building that stood by itself in the center of the cavern. A dozen elderly men sat behind a long table of carved wood that was black and cracked with age. It was, Larry realized, the first wooden thing he had seen since he landed on the Moon. At either side of the chamber stood a squad of armored warriors. Larry was staring at a curious device that was carved in the center of the table, and carried on a banner hung above the heads of the council, and inlaid in a white metal on the bluish steel shields of the
guards. And then he recognized it! It was the crescent Earth, the profile of the mother planet as seen from the Moon when the Americas were still in sunlight and the shadows of night were creeping across the Atlantic. The sight of it made him home-sick. The crescent moon had been a religious symbol to many of the ancient races of Earth, and it was fitting that the crescent earth should hold a similar place on this isolated satellite. It seemed to Larry that Diana was a trifle nervous over something. She had entered the council chamber with an air of confidence, lifting one arm in a stately gesture of greeting and asking the Elders to accept the men from Earth as friends and guests, but he sensed a degree of uncertainty behind her manner. In hasty phrases she told the council of the revolt of part of the Insect-men, and of the timely arrival of the strangers from the mother planet. "And so I request that you accept these men into the Brotherhood of the Caverns!" she finished. The graybeards behind the long table nodded gravely, but before they could speak another voice rang but in a sharp challenge. "And I, O Elders of Chotan, demand that these interlopers be put to death in accordance with the ancient law of the Caverns concerning unwanted strangers!" X The speaker was a fair-haired young man in a green cloak. He looked more like an Earthling than a Lunarian, with his sturdy legs and small eyes. He pointed an accusing finger straight at Larry in a dramatic gesture, and Diana wheeled to face him with anger in her voice. "You talk very loudly of the ancient laws, Xylon, for a newcomer only recently taken into the Brotherhood because you fled as an outlaw from the Lords of Gral-Thala!"
"I did not make the laws!" Xylon retorted. "The death penalty for strangers has not been strictly enforced for many years—or you would not now be alive! It is up to the decision of the Elders!" The council chamber was in an uproar, with shouted phrases flung back and forth. Larry laid a hand on the butt of his ray-gun. A keen- eyed officer of the guards caught the gesture, and instantly Larry found a pair of rifles directed at his chest. At least, they looked like some sort of compressed air rifles. They had fiber stocks, and long barrels, and a cylindrical magazine beneath the barrel. Then a deep voice dominated the tumult as a red-haired man in full armor forced his way through to the forefront of the crowd. "The girl is right, O Elders and members of the Brotherhood!" he boomed. "Xylon talks like a fool. I, Pyatt of Kagan, urge that the strangers from Earth be accepted. Let Xylon remain among us for a little while longer before he attempts to dominate our councils!" Larry could sense the swing of sentiment in their favor, could feel the lessening of the tension. The man called Xylon shrugged and turned away. Then the council took a formal vote, waving the ancient death penalty and allowing the strangers the freedom of the Caverns. One of the Elders near the end of the table rose to his feet. He wore the typical black robes of the Council, but as Larry looked closely at the man's lined face he saw the resemblance to Diana and knew that he was looking at Lester Staunton. "Since these men are from what was once my own land," Staunton said, "I will make them comfortable in my house for the duration of their stay here." As the crowd began to stream out of the council-chamber, the red- headed man pushed his way through to Ripon and Larry. He was unusually burly and big-thewed for a Lunarian, and though his face was marred by a pair of old scars he had a wide and cheerful smile. "Welcome to the Cavern of Chotan!" he boomed. "I am Pyatt of Kagan, military commander of all the armed forces of the Caverns.
Later I will want to talk to you about that revolt of the Insect-men, which is something that has not happened before. Also, we will drink a goblet of wine together." "Then you have wines on the Moon?" Ripon asked, visibly brightening. "Aye, wines of many sorts. Though my own taste runs more to the strong-waters that fire the blood and set a man's head to spinning." "I can see that you and I have a lot in common!" Ripon grinned. Just before they left, Xylon came up to shake hands with Larry. "No hard feelings, Earthling!" he said. "It is just that the safety and liberties of the Caverns are very precious to one like myself, who has so recently become an outlaw, and I did not think that we should take any chances." "That's all right," Larry said shortly. Now that he saw Xylon at really close range, he realized that the man was older than he had thought. His appearance of youth vanished when you saw the many fine wrinkles in his face and the weariness around his eyes. He had a dissolute appearance. Xylon might be sincere in his bid for friendship, but Larry felt that there was something serpentine and evil about the man. With Diana and her father and a few others, they walked along one of the many winding paths of Chotan. Larry noticed that the chemically grown plants had no scent at all. The motionless, warm air was suffused with a misty and golden light. Small, neat houses built in various bright colors stood amid their plots of grass. It was a strange scene to Earthly eyes, that cavern far below the Moon's chill surface, but it was a pleasant spot in its way. The women they passed along the walks were dressed like Diana, in a gayly colored loin-cloth with a narrow band across the breasts.
Most of the men wore a loose, colored cloak in addition to the single garment. Only a few were armed. Larry had taken off the right mitten of his space suit to shake hands with Pyatt and Xylon in the council chamber. Several times he had started to replace the mitten, but something had always distracted him and he was still carrying it in his left hand. Now, as he happened to give the mitten a shake, a small insect of a blood-red color fell out and landed on the walk. It looked something like a miniature scorpion. Larry had only a hasty glimpse before Pyatt of Kagan leaped forward and crushed the crawling thing with the heavy sole of his sandal. "That was a spanto!" he said. "Their bite means death within ten seconds. I wonder how it came to be in your glove!" "I wonder myself!" Larry said grimly, looking across the field at the green-cloaked figure of Xylon, who had turned off on another of the branching walks. It would not have been hard for Xylon to have dropped the insect in his glove! As if in answer to his thought, Diana spoke quietly: "I do not trust Xylon any farther than I can see him, friend Larry! There is something unclean in his eyes when he looks at me." "If he looks at you too much while I'm here I'll break his jaw!" Larry said. The girl looked up at him with a sudden smile that was also a challenge. "I begin to understand why my father has always said that I would like the men from Earth better than the Lunarians!" XI They sat in Professor Staunton's laboratory, a square chamber where Earthly equipment taken from the wreck of his space-ship was mingled with typically Lunarian furniture and equipment. The walls
were light blue, of that polished composition resembling bakelite that was used for building in the Caverns. The walls were about ten feet high, and they ended in an ornamental cornice without any ceiling or roof at all. Overhead there was a glow of misty light, and far above the rocky top of the cavern. "Why should we need roofs?" Diana said in reply to Larry's surprised comment. "Here in these Caverns there is neither rain nor snow nor wind, nor any change in temperature at all. The walls give privacy, and there is no need for anything else." Ripon was bending over a table on which Staunton had spread a large map of the Moon. The cavern of Chotan was indicated by a red dot, and Larry saw that there were a dozen others scattered around within a radius of a few hundred miles. "Our space-cruiser was wrecked near one of the entrances to this cavern when we landed here thirty years ago," Staunton said. "As you have guessed, it was the inability to land safely with rockets, in a practically airless atmosphere where helicopters were useless, that smashed us. As you did, we had fortunately put on space suits before trying to land. Our ship was too badly wrecked for any chance of return." "But how have you succeeded in getting all these people to learn English?" Ripon asked. "They knew that language before I came! But it is best that I give you a hasty outline of Lunarian history. The simple-minded but husky Insect-men were the aboriginal inhabitants of the Moon. Long æons ago, while most of the people of Earth were living crudely in caves and using chipped stones for tools and weapons, an isolated people developed a high civilization in what I have roughly identified as the region of the Himalayas. A series of great earthquakes destroyed their civilization, but a large number of them escaped and came to the Moon in some kind of a space-ship. Here they found, in those days, a small planetary body that had a thin but breathable air. They founded a civilization on the other side of the Moon where it is
always sunny, and called it Gral-Thala. Those were pleasant days, if the old legends are to be believed, the Golden Age of Lunarian civilization." For a moment Staunton paused. All those in the room, including the Lunarians who had been familiar with this tale since childhood, hung intently on his words. The broad face of Pyatt of Kagan was somber and moody as he sat bent forward with the scabbard of his sword resting across his armored knees. "As the centuries passed, the atmosphere continued to thin," Staunton went on, "so the Ancients took care to preserve what was left. Gral-Thala is in the fertile part of the Moon, and lies in a vast valley completely surrounded by a lofty mountain range. By means of the superior engineering knowledge of the Ancients, they built a lofty wall or barrier along the crest of the range so that its top is miles above the level of the valley floor. They then sucked all the air within the Great Barrier. Gral-Thala itself thus lies in a great pool of air surrounded by the ranges and the barrier. On the rest of the Moon, as here, air only remains in deep crevices and caverns like this." "But these caves were a great labor in themselves..." Ripon began. "Originally these caverns were built as outposts of Gral-Thala, built here because of their nearness to valuable mineral deposits. People came out from the sunlit cities within the Great Barrier to put in a tour of duty in the caverns. Again life on the Moon had reached a pleasant equilibrium. And then came the great disaster! Some two centuries ago a group of several hundred outlaws fleeing from Earth came here in a big space-ship." "The Mercury!" Larry exclaimed. "Exactly. Those men and women who came from Earth were few in comparison to the population of the Moon, but they were cruel and
ruthless and they had weapons of war. The peaceful Lunarians had at that time no weapons at all, for they had no need for them. Within a few months the invaders made themselves Lords of all Gral- Thala! That was when English, the language of the invaders, came to be spoken by everybody on the Moon as well as the softer tongue of the Lunarians themselves. A few of the hardier folk in Gral-Thala fled to these caverns as outlaws. The invaders made only half- hearted attempts to come after them, and with the passing of the years the location of these refuges has been forgotten by people living within the Great Barrier. That is why these places are now known as the Lost Caverns." "And the invaders still rule?" "Their descendants are still Lords of Gral-Thala. Cruel and ruthless they always were, decadent and dissolute they have now become as well, but they still rule the sunny valley that was the pride of the ancient Lunarians. They hold the power, and they are aided by a few groups among the people of Gral-Thala who have sacrificed their honor to fawn upon their masters. Our spies, who penetrate beyond the barrier, tell us that before long there will come a day when the people are ready for revolt—but the time is not yet." "But surely!" said Pyatt of Kagan, his deep voice breaking in on the low monotone in which Staunton had spoken, "surely our visitors will return to Earth, now that interplanetary travel has become possible, and bring us the warriors and equipment to storm the high palaces of the tyrants of Gral-Thala!" "I should think that the Confederation of Earth would send help, particularly since the original invaders were outlaws from that planet," Staunton said. "How about it, friend Ripon? How are conditions back on Earth at this time?" Ripon straightened up and shook his shoulders. The glow in his eyes faded away, and the lines in his face deepened once more. "The Lunarians can look for no help from Earth until one thing is accomplished," he said. "I have been letting scientific enthusiasm
make me lose sight of our reason for coming here. How are conditions on Earth, you ask? I can tell you in a single sentence. Unless we of Earth very quickly get a new supply of radium salts suitable for use with the Riesling Method, in a few weeks we all perish!" "I do not understand." In a few hasty phrases Ripon sketched the development of the terrible plague that was so swiftly robbing Earth of its inhabitants. At the end Staunton leaned back in his chair. "Such salts are available on the Moon in ample quantity," he said slowly, and something in the quality of his voice robbed the words of the reassurance they would otherwise have held, "but—they are all located well within the area of the Great Barrier. And the Lords of Gral-Thala would never let you have even a single milligram!" "Then there's only one thing to be done!" Larry stood up and began to peel off his space suit. "If someone will show me the way, I'll go into Gral-Thala and bring out as much of the radiatron extract as I can carry." "And I will go with you!" boomed Pyatt of Kagan. "By Gorton and Laila, mythical gods of the Moon, it will take more than a few of those cold-eyed tyrants to stop us!" XII Time was the thing that counted. The remorseless pressure of minutes and hours that passed and could never be recalled! The tyrants who lorded it over Gral-Thala had no weapons more deadly than the electronic guns that had been common on Earth two hundred years before. A battalion of troops from Earth, wearing armor of dura-steel and carrying ray-guns, could probably have overthrown the Invaders very quickly. But—there was no time! The
toll of the Gray Death was increasing with each passing hour, back there on the Good Green Planet, and the little group on the Moon would have to do what they could without hope of assistance. They could not pause for proper preparations or careful planning. It was only half an Earth day after they had landed on the Moon, time enough to snatch a few hours' sleep, that Larry found himself moving up toward the surface in a slowly crawling cable car. Chotan already lay behind and far below them, and the oxygen indicator fastened to the sleeve of the space suit showed him that the air was thinning rapidly. Colton and Pyatt were with him. All three of them wore space suits of the Lunarian patterns, that had a metal helmet with glass windows at the front and sides, for the difference in design of the space suits from the Sky Maid would have made them too conspicuous. Pyatt had come along because he had often penetrated beyond the Great Barrier in disguise, and a second Lunarian was waiting for them up on the surface. Ripon had also wanted to come, the idea of this daring raid setting the old, reckless light danging in his eyes. Finally he agreed that one of the leaders of the Sky Maid expedition had better remain in the Caverns in case of disaster to the raiders. "That's the hell of getting along in years, young feller!" he rumbled regretfully. "There's nothing I'd like better than to penetrate the barrier with you and pull the whiskers off the tyrants in their lair. A quick wit and a ready weapon! But I couldn't keep up with you younger men if the going gets hot—though I never thought the day would come when I'd hear Crispin Gillingwater Ripon admit a thing like that!—and you'd better go on without me." "We'll be back soon," Larry said. Ripon snorted. "If you're not back in five days I'm coming after you with the crew of the Sky Maid and as many of the folk of the Caverns as I can get to come along!"
The Cavern of Chotan was in that part of the Moon which is sometimes in sunlight and sometimes in darkness, and it was night when they came out of the tunnel. The moisture on the space suit instantly froze into a fine white frost. A few Lunarian sentries waited for them there, and nearly a hundred of the Insect-men. With them were two carts that had high wheels and springs, something like an old-fashioned Earthly buckboard. For a few moments, Pyatt talked to the leaders of the Insect-men in their clicking tongue. The glowing knobs atop their antennae bobbed up and down as they nodded their heads in understanding. Then Pyatt motioned Colton into one of the carts and climbed in beside him. Another Lunarian, slender even in the bulky space suit, climbed into the second cart beside Larry. Pyatt swung his right arm forward. A score of the Insect-men instantly scampered ahead as scouts, spreading out like the spokes of a fan. Small parties went out to either flank. The rest, about thirty to each cart, gripped the trailing ropes and darted ahead with the wagons following behind them. They went at almost incredible speed, the four legs of each giving them a steady drive. Even though the Insect-men were picking the smooth stretches of the rock and were evidently following a definite though unmarked trail, it was rough going. The light wagons jolted and banged as they whizzed along, and Larry had to cling to the rail with both hands to keep from being thrown off. "Is all the way as rough as this?" he panted to his companion. "Better soon," the Lunarian said shortly. After about three hours they turned into a smooth and level road. It wound up and down over the rolling rocky plain, evidently a highway of great age. Occasionally they passed crumbling ruins beside it. Larry supposed that the road and the ruins dated back to those very
ancient days before the Lunarians withdrew their shrinking supply of air within the Great Barrier. Now that the road was smooth, the Insect-men pulled the carts along at a whizzing pace. The light wheels whirred as the wagons shot ahead. The scene, Larry reflected, was like a nightmare. All about him were the chill mountains and craters of the Moon, lifting their jagged peaks against the cold stars. Ahead of the speeding wagon ran the toiling cluster of Insect-men, their hard shells gleaming faintly in the starlight and their glowing antennae bobbing in a swift rhythm as they ran. The treads of the wheels rattled on the rocky surface of the road, the horny feet of the Insect-men made a steady scraping sound as they ran. The two men seated in the cart ahead were monstrous and misshapen figures in their space suits. Larry's companion had remained sullenly silent, in spite of several efforts to start a conversation. This was unusual in one of the normally pleasant and talkative Lunarians, but Larry had not thought much about it. Now, as he made some remark about the speed of their progress, he heard a low chuckle and in his earphones sounded the voice of Diana Staunton. "Yes, Larry, we travel fast. In a few days we will enter the zone of sunlight." "You," he exclaimed. "This expedition is too dangerous. I would never have let you come if I had known." "Why else do you think I kept so silent until now, when it is too late to send me back?" she asked, and though he could not see her face through the glass of her helmet in the darkness he could tell that she was smiling. "Neither would Pyatt of Kagan or my father have let me come. I stole the space suit of the young man who was to accompany you and left him locked in a storeroom." "You will have to remain outside when we go within the barrier." "Where you go, I go," she said with finality.
Sunrise on the Moon! There was no sudden onslaught of light as on the Earth, for the Moon day was twenty-eight days long! Yet, as they progressed steadily toward the horizon, the Moon's rotation brought the edge of the sun gradually into sight above the barren horizon, and as the days passed, a blinding glare of light swept in upon them and they moved the dark glasses into place in front of the windows of their space-suit helmets. The temperature rose rapidly with the coming of the two weeks' sunlight, and before long the frost on the space suits was melting. Then, stretching along the crest of a mighty mountain range ahead, Larry saw a lofty gray wall that went so high its top was almost lost from view above. They had come within sight of the Great Barrier! XIII Several times along the way they had been halted by sentry-patrols from some of the other outlaw caverns, who warned them that an unusual number of strong parties of troops from Gral-Thala were roaming the waste-land. However, they came without incident to a tiny outlaw hide-out. This was within half a mile of one of the caverns that was under the domination of the Lords of Gral-Thala. Two hours later Larry and the others stood with a score of other people, in an air-lock in a great tunnel that led through the mountain range and into Gral-Thala. All these people were residents of the valley returning from a tour of duty in the caverns, and the four outlaws from Chotan had been furnished with forged documents that gave them the same identity. The space suits had been removed and hung on numbered racks. The three men wore the tight tunics and loose trousers that were the customary dress within the valley, as distinguished from the loin
cloth and cloak of the cavern outlaws. This was fortunate, for the trousers concealed the sturdy Earthly legs of Larry and Colton which would have stood out in sharp contrast to the typical spindly shanks of the otherwise well-built Lunarians. Diana wore a loose robe, with tight wrappings concealing her hair and a thin veil over her face. A heavy guard of soldiers checked the papers of all the travelers before they let them through. These troops wore light armor, and each carried an electronic gun slung from his shoulder. The officers were evidently of the Invaders, cruel-eyed men cast in the same mold as Xylon. The men were Lunarians, generally of a rather debased type and drawn from among the worst element in the population. A heavy-featured trooper glanced at Larry's papers in a perfunctory manner, then handed them back. "All right, all right!" he growled. "Get along. Don't block the way!" The tunnel ended on the inner slope of the mountain range surrounding Gral-Thala, where many cars ran down the steep incline into the city below. It was a pleasant and smiling land that Larry Gibson saw before him, a sunlit and fertile valley so vast that even the lofty range on the far side was invisible over the horizon. Towns and villages dotted the plain. Farms lay among their fertile fields. A small river wound through the center. Directly below him, clustered against this part of the valley wall, was a mighty city. "This is the city of Pandonaria," Diana's voice came softly through her veil, "capital city of Gral-Thala." The city itself was a terraced mass of colored buildings cut by many streets and interspersed with gardens. Several towering palaces of white and gold, the abodes of the Lords of Gral-Thala, dominated the lower buildings. It was good to see real sunlight again! To see birds flying overhead! To smell the odor of flowers and growing things, in contrast to the flat and motionless air of the Lost Caverns! It was hard to believe that this pleasant spot was really the scene of such a brutal tyranny as he had been told. Then they rounded a bend in the sloping road and came to an abrupt halt.
At the side of the road stood a sort of gallows, made of strips of a ruddy metal bolted together. From it hung the nude body of a young Lunarian girl. She was suspended by her bound wrists high above her head, and her feet swung far off the ground. From the clotted blood at her bound wrists, and the way the eternal sun of the valley had burned her skin, Larry knew that she had hung there many hours. The girl was far gone but she was not yet dead. At intervals her drooping head moved feebly from side to side. A pair of armored soldiers leaned on their weapons below the gallows. Around the girl's neck hung a sign, lettered in the archaic English script that was the official language of Gral-Thala: "THIS GIRL DARED STRIKE ONE OF THE NOBLES OF GRAL-THALA WHO CONDESCENDED TO NOTICE HER." Fierce anger filled Larry Gibson's heart, a consuming anger that set his clenched fists shaking. For some reason he thought of Diana. Though she stood only a few feet away from him, he visioned her hanging from such a gallows if the dissolute tyrants of this land ever stormed the Lost Caverns. Then Pyatt of Kagan laid a hand on his arm. "Careful, my friend!" the Lunarian hissed. "Your anger shows on your face, and that is bad. We cannot help that poor girl now. Come!" They went down into the city, avoiding the broad boulevards and keeping to the narrower streets where the poorer people were. As they passed by the base of one of the high palaces, they came to the body of a girl who lay crushed on the stones and had evidently been thrown or jumped from one of the upper windows. An aged man stood astride the body, leaning back and shaking his skinny fists at the white and gold bulk of the palace above him. "Woe be upon the Lords of Gral-Thala!" he screamed in his shrill old voice. "Triple woe upon the tyrants and upon the decadent parasites who fawn upon them. Evil lies in wait for ye, lurking in your white
palaces with your guards and your harlots! The hour of doom is not far away! The vengeance of Gorton and Laila may be long delayed, but it comes in the end! Woe to the Lords of Gral-Thala!" An uneasy, sullen, murmuring crowd was gathered around the ragged old man although they left a broad circle of vacant space around him and the body of his granddaughter. A few troopers of the garrison were making a half-hearted effort to push the crowd back. They were uncomfortable in the face of the unspoken but obvious hatred of the throng. Larry and the others prudently kept to the back of the crowd. Even so, they were near enough to see what happened next. Silver bells rang sharply, and lackeys called an arrogant summons to clear the way. In the midst of a circle of armed guards, porters carried a swaying gilt litter. On the cushions of the litter rested a man. It was one of the nobles of Gral-Thala, a perfumed degenerate in silken robes with a rouged and painted face. For a moment he stared at the crowds with his arrogantly scornful eyes. Then, as he saw the old man beside the girl's body and heard the curses he was shouting, his patrician face was distorted into a sneering frown. The noble snarled an order, and one of his guards lifted his electronic rifle. There was a flash of blinding light! A sudden clap of miniature thunder, and a smell of ozone. The man-made lightning bolt struck the old man in the chest and knocked him sprawling across the body of his granddaughter. With a faint smile the noble leaned back on the cushions of the litter and waved languidly to his porters to move on again. "Let us go, my friends!" Pyatt whispered hoarsely. "We cannot right all the wrongs of Gral-Thala at one stroke, and our mission is the most important thing at the moment." XIV
They were walking slowly down one of the quiet streets of the city, a quarter where there were few guards and little chance of discovery. Larry noticed that all the windows were equipped with heavy shutters, so that the light could be closed out when the inhabitants of this land desired to sleep. It was a place of unending daylight, always turned toward the sun, where darkness never came. Colton was more interested in the metal rails that ran along the walks on the outside of the buildings. "My Lord!" he said softly, "These are gold!" "Of course," Pyatt of Kagan said absently, "Gold is one of the most common metals in Gral-Thala. Our problem is the matter of the radium salts. I happen to know that they are stored in small boxes made of ura-lead, in one of the government storehouses. It would be easier to steal some direct from the mines, but there is no time for that because of the question of proper packing and handling. We must risk everything on a bold attempt to raid the warehouses." "Suits me," Larry said quietly. Just then Diana gripped him by the arm and jerked him back against the wall of the nearest building. "Look there!" she hissed. Another litter was passing along the cross street just ahead of them. This litter went in evident haste, with lackeys swinging whips to clear the path and the passenger bending forward to urge his bearers to greater haste. The man who rode in the litter was Xylon! The four outlaws stared at each other in grim and ominous surprise. There had been no doubt of the identity of the man who had just passed within a few yards of them. "But what does that mean?" Larry gasped. "It means that I have been a fool!" Pyatt snarled. "Xylon is evidently no outlaw who came to the caverns to seek shelter, but a spy sent out by the Lords of Gral-Thala. Now I understand the reason for that revolt among the Insect-men! He must have stirred it up in an attempt to kidnap Diana here because of her hold over those simple
creatures. Now the location of the Lost Caverns is at last known to the tyrants, and there will be an attack in force." "And Xylon knows that we are here in Pandonaria!" Diana exclaimed. "Which means that all our lives hang by a thread no heavier than a woman's hair! We must get under cover at once! Then we will send word back to the Caverns by secret radio, that they may prepare for an assault. After that we will plan an attempt on the radium salts." The outlaws of the Lost Caverns had certain confederates within the city, and they now took refuge in the house of a small merchant who was a distant cousin of Pyatt. Larry watched as Pyatt and the merchant crouched over the sending set concealed in a small closet built in the thickness of one of the walls, the arkon-bulbs flashing as they sent the warning to Chotan to be spread to the other caverns. At last Pyatt straightened up. "At least that is done," he said. "Now we will wait two hours, which will be the time of the Third Meal. There will be few people on the streets, and the warehouse guards will be drowsy, and we will have our best chance." Pyatt and Colton had gone somewhere else in the house, and Larry sat with Diana in a small room whose windows looked out on the green fields beyond the city. The girl had loosened her blue veil so that it hung in soft folds about her chin. "This is the first time in my life I have been anywhere but in the Caverns and on the waste-land," she said moodily. "This valley of Gral-Thala is a pleasant place." "You would like Earth even better." "I suppose I would. Will you take me back to that Earth of yours when you return, Larry?"
"Not until the Gray Death is overcome! I would not want to take any chance of it striking you down." "Do you love me, Larry?" she asked, without either coquetry or embarrassment. "I guess I do. Of course, we've only known each other for a few hours—but I guess I do." "I am glad," she said simply. The two hours passed, and Pyatt came striding back into the room. They had given him one of the ray-guns brought ashore from the Sky Maid, and he carried it thrust in his girdle close to his hand. "It is time to go," he said. "We must make our attempt now, win or lose. Where is Colton?" "I thought he was with you." "Haven't seen him in two hours!" A hasty search of the merchant's house and small grounds revealed no trace of the missing officer. Pyatt stood glowering blackly and pulling at his chin. "I don't like it," he said. "Yet, if the soldiers had taken him, they would have come for us as well." A different thought was running through Larry's mind, a grim and unpleasant suspicion. He was remembering Colton's past history ... his general sullenness ... the greed that he had shown throughout the entire expedition. He was also remembering that he had seen Colton in deep conversation with Xylon a few hours before they had left Chotan. "I am afraid," he said bitterly, "that Colton has sold us out to Xylon and the Lords of Gral-Thala for promise of reward. We had better get out of this house right away, before...." Larry never finished that sentence. There was a roaring crash, and the door was shattered by the impact of a pair of electronic bolts
fired by the soldiers who had crept up to the house. Armored figures came pouring in the door! Others were at the back. Pyatt of Kagan, fighting furiously, went down under press of numbers. Larry managed to get his ray-gun up and fire one blast that crumpled a charging trooper in mid stride, but then half a dozen gripped him and the brief fight was over. They were taken! XV The hands of the three prisoners were tied behind their backs, and nooses were placed around their necks. Then they were dragged out into the street. The merchant was not taken prisoner at all, simply killed out of hand with the body left lying across his shattered threshold. A thin-lipped, hooked-nosed officer spat in Larry's face as he was led past the body of the dead merchant. "Not for you will there be such an easy ending," he sneered. "An example is to be made. You will die before crowds, in the Plaza of the Four Virgins, and the process will be a slow one." They were surrounded by a double rank of guards as they were led along by the nooses about their necks. All three had been stripped to a loin cloth, and the sun was scorching hot upon Larry's back and shoulders. At least, he thought thankfully, Diana's long black hair gave her some protection. There were jeers and hoots as they were led through the crowded streets, but most of them came from members of the tyrant class and from the few over-dressed and foppish Lunarians who aped their masters. The mass of the people gazed in stony and somehow sympathetic silence. Into one of the tall white-and-gold palaces of the Lords of Gral-Thala they were taken, and down into stone-walled dungeons far underground. They were placed in a single cell. They stood with their backs against the walls, arms out-stretched and wrists lashed
to rings set in the stone, able to move little more but their heads. Then, for a while, they were left alone. "Well," said Larry with grim humor, "here we are." "So it seems!" Pyatt's voice was rasping and bitter. "I am indeed a fool for ever having allowed Xylon to live in the Cavern of Chotan, in spite of the kind-hearted ruling of the Elders." "What will they do with us?" Larry asked. Pyatt hesitated, licking his lips and glancing at Diana, but the girl answered for herself. "We shall probably be skinned alive in the public square, dying slowly under the torture," she said. "It is the favorite punishment of the tyrants for those they particularly hate." It was a day of triumph for the Lords of Gral-Thala. Xylon's triumphant return with the information that would lead to the wiping out of the always troublesome outlaws of the Lost Caverns, and the capture of the three prisoners, made it a holiday for the ruling class of the valley. They came in hundreds to see the three captives. The famous military leader of the outlaws ... the girl who was considered a goddess by the primitive Insect-men of the waste-land ... the the stranger from that distant Earth whence their own ancestors had fled. They came to throng the dungeon corridor and stare in at the trio of captives spread-eagled against the wall of the cell. Larry watched them through the barred door. For hours on end there were always a few of them in the corridor, staring and jeering. Foppish men in white and gold with their curled hair laden with scent. Haughty and jewel-clad women whose sharp featured faces held even more cruelty than their male companions. Many were attended by Lunarian slave girls whose fettered hands held their trains up from the floor, and the bare backs of the slave girls were usually marked with the crossing red marks of whips. Larry knew, now, that the tales told in the Caverns about the cruelty of the Lords of Gral-Thala had not been exaggerated.
Xylon came to see them after a while, opening the cell door and walking in to stand sneering at them with his thumbs hooked in his jeweled girdle. "Colton sold you out for the promise of wealth and a place in the ranks of our nobles," he said. "It will be a pleasure to watch you die." For a moment he walked over to stand in front of Diana who looked back at him with an expressionless face. "You are not a bad- looking wench. I can take you for one of my slaves if you wish to be agreeable." "I would rather go with an Insect-man!" the girl said with calm scorn. Xylon shrugged and turned away. "So be it. At that, it would be a pity to rob the crowd of the pleasure of watching you die." As near as Larry could judge it, the equivalent of an Earthly day had passed before they were taken out of the cell. They were given an hour to ease their stiffened muscles. Then the guards bound their wrists before them, and by the trailing ends of the ropes led them out of the dungeons and through the streets to a broad open space just at the foot of the inclines that led down from the tunnel by which they had entered the city. The Plaza of the Four Virgins, named from the four gigantic statues of polished stone that had been placed at its corners in some long ago day before the Invaders came, was a vast paved space in front of an ancient temple that was now used as a government building. In front of the temple a metal scaffold had been erected with two heavy uprights and a cross-piece. The rulers of Gral-Thala were sprawled in cushioned ease on the steps of the temple, well guarded by their troops, and the floor of the Plaza was filled with the common people of the city. These latter were present in great number, a silent and ominously sullen mass. The three prisoners were stood in a row on the scaffold. Their hands were raised above their heads, and the ropes made fast to the cross- piece so that they were held tautly erect and motionless. Sharp
Welcome to our website – the ideal destination for book lovers and knowledge seekers. With a mission to inspire endlessly, we offer a vast collection of books, ranging from classic literary works to specialized publications, self-development books, and children's literature. Each book is a new journey of discovery, expanding knowledge and enriching the soul of the reade Our website is not just a platform for buying books, but a bridge connecting readers to the timeless values of culture and wisdom. With an elegant, user-friendly interface and an intelligent search system, we are committed to providing a quick and convenient shopping experience. Additionally, our special promotions and home delivery services ensure that you save time and fully enjoy the joy of reading. Let us accompany you on the journey of exploring knowledge and personal growth! ebookultra.com

More Related Content

PDF
The Discovery of Global Warming Spencer R. Weart
byiishiprofy
 
PDF
The Discovery Of Global Warming Illustrated Edition Spencer R Weart
byachadogorio
 
PPTX
Climate Change: What we really Know?
byArfar M. Razi
 
DOCX
Climate Change
byJames Stevens
 
PPT
Course 7/7 Vladimir jankovic
byenvironmentalconflicts
 
PDF
Climatic Changes Since 1700 1st Edition Stefan Brnnimann
bykamnarolphp2
 
PDF
Climatic Changes Since 1700 1st Edition Stefan Brnnimann
bykamnarolphp2
 
PPT
L spina climch-evidence
byGladys Baya
 
The Discovery of Global Warming Spencer R. Weart
byiishiprofy
 
The Discovery Of Global Warming Illustrated Edition Spencer R Weart
byachadogorio
 
Climate Change: What we really Know?
byArfar M. Razi
 
Climate Change
byJames Stevens
 
Course 7/7 Vladimir jankovic
byenvironmentalconflicts
 
Climatic Changes Since 1700 1st Edition Stefan Brnnimann
bykamnarolphp2
 
Climatic Changes Since 1700 1st Edition Stefan Brnnimann
bykamnarolphp2
 
L spina climch-evidence
byGladys Baya
 

Similar to The Discovery of Global Warming Spencer R. Weart

PPT
Lesson1 climate and change GCSE Edexcel B Geography
bysarah marks
 
PDF
New Climate Change Statement from the American Meteorological Society
byEarth Institute of Columbia University
 
PPT
Swechha - London Colder than Antarctica" Unusual Trends of Global Cooling
byNeeraj Parashar
 
PPTX
Climate Change Past Present Future
bySERC at Carleton College
 
DOCX
Global warming
bylideuno
 
DOCX
New microsoft office word document
bySanthosh Gowda
 
PPTX
Poteplenie klimata O. Gunder_11-b
byJulia Birhova
 
PDF
Journal of Environmental & Earth Sciences | Vol.4, Iss.2 October 2022
byBilingual Publishing Group
 
DOCX
Felicia's junior paper
byfelicia7194
 
PPT
Climate changes past and future
byDocumentStory
 
PDF
Earth's Temperature _ A Brief History Of Recent Changes
byIngre1930685
 
PPT
Global Warming
byJeff Phipps
 
PDF
A Note on “Weather and Climate” and “Global Warming and Climate Change”: Thei...
byBRNSSPublicationHubI
 
PDF
Trends in-extreme-weather-events-since-1900--an-enduring-conundrum-for-wise-p...
byAnochi.com.
 
DOC
Atmosphere on the move
bythompsonlr
 
PPT
Climate change part 1
byEd Stermer
 
PDF
Historical Climate Variability And Impacts In North America Dennis B Blanton
byaxjpwioyiv1564
 
PDF
IPCC 2013 report on Climate Change - The Physical Basis
byGreenFacts
 
PPT
Climate change part 1
byguest8a23e5
 
PDF
The Science of Global Warming.pdf
byBillyCripe1
 
Lesson1 climate and change GCSE Edexcel B Geography
bysarah marks
 
New Climate Change Statement from the American Meteorological Society
byEarth Institute of Columbia University
 
Swechha - London Colder than Antarctica" Unusual Trends of Global Cooling
byNeeraj Parashar
 
Climate Change Past Present Future
bySERC at Carleton College
 
Global warming
bylideuno
 
New microsoft office word document
bySanthosh Gowda
 
Poteplenie klimata O. Gunder_11-b
byJulia Birhova
 
Journal of Environmental & Earth Sciences | Vol.4, Iss.2 October 2022
byBilingual Publishing Group
 
Felicia's junior paper
byfelicia7194
 
Climate changes past and future
byDocumentStory
 
Earth's Temperature _ A Brief History Of Recent Changes
byIngre1930685
 
Global Warming
byJeff Phipps
 
A Note on “Weather and Climate” and “Global Warming and Climate Change”: Thei...
byBRNSSPublicationHubI
 
Trends in-extreme-weather-events-since-1900--an-enduring-conundrum-for-wise-p...
byAnochi.com.
 
Atmosphere on the move
bythompsonlr
 
Climate change part 1
byEd Stermer
 
Historical Climate Variability And Impacts In North America Dennis B Blanton
byaxjpwioyiv1564
 
IPCC 2013 report on Climate Change - The Physical Basis
byGreenFacts
 
Climate change part 1
byguest8a23e5
 
The Science of Global Warming.pdf
byBillyCripe1
 

Recently uploaded

PPTX
Historical Background of Pharmacy .pptx
bySneha Gaurkar
 
PPTX
Tablets & Liquid orals Industrial pharmacy-I UNIT-2, B. Pharam V Semester PPT
byARUN KUMAR
 
PDF
Principle, Construction, and Types of Varactor Diode – A Comprehensive Lectur...
byGS Virdi
 
PPTX
Improved ui_ux in Odoo 18.2 Purchase in Odoo 19
byCeline George
 
PPTX
THERAPEUTIC COMMUNICATION for 2nd year GNM, 2ND YEAR P.B.B.SC NSG, 5TH SEM B....
byparmarjuli1412
 
PDF
Plant Germplasm: The Foundation of Crop Breeding, Genetic Diversity and Food ...
bySatyam Sharma
 
PDF
How to (Re)Build Your District's Enrollment Numbers
byMebane Rash
 
PPTX
DepEd_ARAL_Program_Orientation FINAL COPY.pptx
byAljohnEspejo1
 
PPTX
Gender, School and Society - B.Ed Course
byRejoshaRajendran
 
PPTX
Everything You Need to Know About Actions in Odoo 18
byCeline George
 
PDF
JRF Plant Science Syllabus | Complete Unit-Wise Discussion & Preparation Stra...
bySatyam Sharma
 
PPTX
PLAY-IMPORTANCE OF PLAY,FUNCTIONS OF PLAY AND TYPES
byBHUVANESHWARI BADIGER
 
PPTX
What is Scheduled Actions in Odoo 18
byCeline George
 
PPTX
An inclusive AI - Supporting students with special education needs by Andreas...
byEduSkills OECD
 
PDF
how to write your research instrument.pdf
byThelma Villaflores
 
DOCX
ANATOMY NOTES- Dr. Sudhadevi Sadanandan
byDr. Sudhadevi Sadanandan
 
PPTX
Overview of Cash on delivery in Odoo 19
byCeline George
 
PPTX
Overview of Uploading a bill in Odoo 19
byCeline George
 
PPTX
Unit 6- Heme Catabolism.pptx............
byAkanksha Kotangale
 
PPTX
How to configure Client action in odoo 18
byCeline George
 
Historical Background of Pharmacy .pptx
bySneha Gaurkar
 
Tablets & Liquid orals Industrial pharmacy-I UNIT-2, B. Pharam V Semester PPT
byARUN KUMAR
 
Principle, Construction, and Types of Varactor Diode – A Comprehensive Lectur...
byGS Virdi
 
Improved ui_ux in Odoo 18.2 Purchase in Odoo 19
byCeline George
 
THERAPEUTIC COMMUNICATION for 2nd year GNM, 2ND YEAR P.B.B.SC NSG, 5TH SEM B....
byparmarjuli1412
 
Plant Germplasm: The Foundation of Crop Breeding, Genetic Diversity and Food ...
bySatyam Sharma
 
How to (Re)Build Your District's Enrollment Numbers
byMebane Rash
 
DepEd_ARAL_Program_Orientation FINAL COPY.pptx
byAljohnEspejo1
 
Gender, School and Society - B.Ed Course
byRejoshaRajendran
 
Everything You Need to Know About Actions in Odoo 18
byCeline George
 
JRF Plant Science Syllabus | Complete Unit-Wise Discussion & Preparation Stra...
bySatyam Sharma
 
PLAY-IMPORTANCE OF PLAY,FUNCTIONS OF PLAY AND TYPES
byBHUVANESHWARI BADIGER
 
What is Scheduled Actions in Odoo 18
byCeline George
 
An inclusive AI - Supporting students with special education needs by Andreas...
byEduSkills OECD
 
how to write your research instrument.pdf
byThelma Villaflores
 
ANATOMY NOTES- Dr. Sudhadevi Sadanandan
byDr. Sudhadevi Sadanandan
 
Overview of Cash on delivery in Odoo 19
byCeline George
 
Overview of Uploading a bill in Odoo 19
byCeline George
 
Unit 6- Heme Catabolism.pptx............
byAkanksha Kotangale
 
How to configure Client action in odoo 18
byCeline George
 

The Discovery of Global Warming Spencer R. Weart

  • 1.
    The Discovery ofGlobal Warming Spencer R. Weart download pdf https://ebookultra.com/download/the-discovery-of-global-warming-spencer- r-weart/ Discover thousands of ebooks and textbooks at ebookultra.com download your favorites today!
  • 2.
    We have selectedsome products that you may be interested in Click the link to download now or visit ebookultra.com for more options!. Global Warming 1st Edition Natalie Goldstein https://ebookultra.com/download/global-warming-1st-edition-natalie- goldstein/ Role of the Government The Confronting Global Warming 1st Edition Jacqueline Langwith https://ebookultra.com/download/role-of-the-government-the- confronting-global-warming-1st-edition-jacqueline-langwith/ Climate Confusion How Global Warming Hysteria Leads to Bad Science Pandering Politicians and Misguided Policies that Hurt the Poor First Edition Roy Spencer https://ebookultra.com/download/climate-confusion-how-global-warming- hysteria-leads-to-bad-science-pandering-politicians-and-misguided- policies-that-hurt-the-poor-first-edition-roy-spencer/ Global Warming The Complete Briefing 5th Edition John Houghton https://ebookultra.com/download/global-warming-the-complete- briefing-5th-edition-john-houghton/
  • 3.
    Global Warming Understandingthe Forecast 2nd Edition David Archer https://ebookultra.com/download/global-warming-understanding-the- forecast-2nd-edition-david-archer/ Encyclopaedia of global warming Vol 2 1st ed. Edition Syed https://ebookultra.com/download/encyclopaedia-of-global-warming- vol-2-1st-ed-edition-syed/ Encyclopedia of global warming climate change 2nd edition Edition Philander https://ebookultra.com/download/encyclopedia-of-global-warming- climate-change-2nd-edition-edition-philander/ Global Warming in the 21st Century 1st Edition Juliann M. Cossia https://ebookultra.com/download/global-warming-in-the-21st- century-1st-edition-juliann-m-cossia/ Global Warming and the American Economy A Regional Assessment of Climate Change Robert Mendelsohn https://ebookultra.com/download/global-warming-and-the-american- economy-a-regional-assessment-of-climate-change-robert-mendelsohn/
  • 5.
    The Discovery ofGlobal Warming Spencer R. Weart Digital Instant Download Author(s): Spencer R. Weart ISBN(s): 9780674011571, 0674011570 Edition: illustrated edition File Details: PDF, 3.31 MB Year: 2003 Language: english
  • 6.
    1 Mason (1957), p.192. THIS IS THE TEXT OF AN ESSAY IN THE WEB SITE “THE DISCOVERY OF GLOBAL WARMING” BY SPENCER WEART, HTTP://WWW.AIP.ORG/HISTORY/CLIMATE. JUNE 2007 HYPERLINKS WITHIN THAT SITE ARE NOT INCLUDED IN THIS FILE. FOR AN OVERVIEW SEE THE BOOK OF THE SAM E TITLE (HARVARD UNIV. PRESS, 2003). COPYRIGHT © 2003-2007 SPENCER WEART & AMERICAN INSTITUTE OF PHYSICS. Chaos in the Atmosphere Before they could understand how climates change, scientists would have to understand the basic principles for how any complicated system can change. Early studies, using highly simplified models, could see nothing but simple and predictable behavior, either stable or cyclical. But in the 1950s, work with slightly more complex physical and computer models turned up hints that even quite simple systems could lurch in unexpected ways. During the 1960s, computer experts working on weather prediction realized that such surprises were common in systems with realistic feedbacks. The climate system in particular might wobble all on its own without any external push, in a “chaotic” fashion that by its very nature was unforeseeable. By the mid 1970s, most experts found it plausible that at some indeterminate point a small push (such as adding pollution to the atmosphere) could trigger severe climate change. While the largest effects could be predicted, important details might lie forever beyond calculation. Few natural phenomena change so radically and unpredictably as the daily weather. Meteorologists had long understood how the atmosphere in a given locality could be capricious and unstable from hour to hour. As one authority explained in 1957, tiny disturbances in the air, far below the limits of observation, could grow into large weather systems within a few days. Nobody could predict these unstable processes, so “there is an effective time barrier beyond which the detailed prediction of a weather system may well remain impossible.” Beyond that limit, which might be only a few days, one could only look to statistics, the probability of rain or frost in a given month.1 Climate was expected to be steadier. Climate was the statistics, defined as a long-term average. The daily fluctuations, people assumed would cancel one another out over the long run, for the atmospheric system was supposed to be self-stabilizing. True, it was undeniable that even a large system could be unstable. Back around the end of the 19th century, the great French mathematician Henri Poincaré had noted that even the orbit of a planet could depend on some tiny fluctuation, as difficult to predict as whether a ball rolling down a knife-edge would fall to left or right. In the 1920s, quantum physicists showed that a lack of certainty was altogether fundamental. This was Werner Heisenberg’s Uncertainty Principle, made vivid by Erwin Schrödinger’s fable of a cat that might be alive or dead depending on the strictly random decay of a single atom. These ideas worked their way only gradually into common awareness. For decades, scientists who studied complex systems mostly just ignored the ideas. Few questioned that the automatic self-correction of the great natural systems would always keep planets in their accustomed orbits, and that over future decades the rains would fall pretty much as they had in the past.
  • 7.
    Weart DGW 6/07Chaos - 2 1 Russell (1941), p. 91. 2 Landsberg (1941, rev. ed. 1947, 1960), pp. 261-268; he cites Brückner (1890a). Of course, anyone who lived through the harrowing Dust Bowl drought of the 1930s, or heard grandfathers talk about the freezing winters of the 1890s, knew that climate could be seriously different from one decade to the next. Few wanted to explain this as mere random drifting. Surely nature was not altogether capricious? Every change must have its specific explanation. Perhaps, for example, rainfall decreased when soils were dried up by overgrazing, and perhaps cold spells followed an increase in smoke from volcanic eruptions. Even more popular than this idea of particular causes for particular deviations was an assumption that features of nature follow periodic patterns, diverging only to return. Things from tides to rabbit populations go through regular cycles, and it was easy to suppose that climate too was cyclical. The idea fascinated many professional and amateur meteorologists. If you could detect a regular cycle in climate, you could develop a scientific explanation for climate change, and use it to calculate predictions of economic value—and perhaps make a killing on the wheat futures exchange! From the 19th century forward, then, people who liked to play with data labored to extract climate cycles from weather statistics. One or another worker discovered a plausibly regular rise and decline of temperature or of rainfall over months or decades in this region or that. Given enough different bodies of data, people could also turn up correlations between a weather cycle and some other natural ebb and flow, notably the eleven-year cycle of sunspots. A 1941 U.S. Weather Bureau publication noted that some 50 climate cycles had been reported, ranging from days to centuries (not to mention the ice ages, which seemed to come and go regularly over hundreds of thousands of years). “Each man who has proposed one or more of these cycles,” the Bureau remarked, “has become convinced that he has found a particular rhythm.”1 Many meteorologists repudiated the whole enterprise, seeing nothing but random fluctuations from the norm. There remained a good number who believed that cycles were probably there, just at the edge of what the data could prove. An indicator of middle-of-the-road opinion was Helmut Landsberg’s authoritative climatology textbook of 1941. Among other cases, Landsberg described how “widespread attention” had focused upon a cycle of around 33 years in the level of lakes (which gave a good measure of average precipitation). Detected in the 1890s, the cycle had been used to predict how much rain would fall in the late 1920s—but the prediction had failed ignominiously. Nevertheless, Landsberg thought there was a real effect at work, perhaps an irregular rhythm that varied between 30 and 40 years long. “Scientific skepticism is well warranted in the research on climate cycles,” he admitted. “Nevertheless some of them seem to have much more than chance characteristics...”2 Meanwhile the stock of weather observations increased rapidly and calculation techniques improved, so that it became increasingly possible to offer solid proof of whether or not a given cycle was valid. The answers were usually negative. By the middle of the 20th century, opinion among meteorologists was divided about the same way as at the start of the century. Some expected that a few cycles would eventually be pinned
  • 8.
    Weart DGW 6/07Chaos - 3 1 Fultz et al. (1959). 2 Bjerknes (1921). 3 Lorenz (1967), p. 124. 4 Fermi et al. (1965), see introduction by S. Ulam, pp. 977-78; Metropolis (1992), p.129; note also Ulam (1976), pp. 226-28. down, while others believed that no cycles existed—the variations of climate were purely random. Progress was stymied unless clues could be found in some new approach. A big clue came in the 1950s, when a few scientists decided to build actual physical models of climate. Perhaps if they studied how a fluid behaved in a rotating pan, they would learn something general about the behavior of fluid systems like the rotating planet’s atmosphere. These “dishpan” studies turned out to be surprisingly effective in modeling features of the atmosphere like weather fronts. What was most thought-provoking was the way the circulation of a fluid in the laboratory could show different patterns even when the external conditions remained the same. Poke the fluid in the rotating dishpan with a pencil, and you couldn't predict which of two or three possible states the circulation would settle into. The choice of pattern depended in some arbitrary, unpredictable way on the system’s past history.1 Of course, random behavior could be no surprise to anyone who watched the tumbling of fluids. When water flows through a channel, if the speed gradually increases, at some point the smooth, steady flow gives way to a turbulent flow with vortexes swirling unpredictably. In 1921, Vilhelm Bjerknes had suggested that a similar instability might be at the root of major daily disturbances of the atmosphere. Beyond some critical point, the symmetric flow of wind would become unstable and spin off storms.2 In 1956, Edward Lorenz proposed an explanation along those lines for the dishpan experiments. As the dishpan experiments were refined, however, they seemed to point to something much more unfamiliar.3 A second essential clue came from another new field, digital computation. As scientists applied computers to a variety of tasks, oddities kept popping up. An important example came in 1953 when a group at Los Alamos, led by the great physicist Enrico Fermi, used the pioneer computer MANIAC to study how a complex mechanical system behaved. They wrote equations that described a large number of “nonlinear” oscillators (the mathematical equivalent of springs with flaws that kept them from stretching smoothly), all coupled to one another. Physical intuition insisted that the distribution of energy among the oscillators in such a system should eventually settle down into a steady state, as a shaken glass of water will gradually come to rest. That was indeed what Fermi’s group saw, after the computer had ground away at the numbers for a while. Then one day, by accident, they left the computer running long after the steady state had been reached. Fermi’s group was amazed to find that the system had only lingered for a while in its steady state. Then it reassembled itself back into something resembling the initial distribution of energy. Like the flow in the rotating dishpan, the system had at least two states that it could flip between for no obvious reason. Further computer experiments showed that the system shifted unpredictably among several “quasi-states.”4 In retrospect, this was the first true computer
  • 9.
    Weart DGW 6/07Chaos - 4 1 The authors called these “ergodic” fluctuations. Eriksson and Welander (1956), see p. 168. 2 Richardson (1922); Rossby (1959), p. 30 [this is a translation of Rossby (1956)]; recent analysis shows that Richardson’s primitive computation could have succeeded fairly well if he had started with perfect data. But his process of computation with a large time-step grossly experiment, with an outcome that foreshadowed much that came later. The lesson, scarcely recognized at the time, was that complex systems did not necessarily settle down into a calm stable state, but could organize themselves in surprising large-scale ways. Fermi’s group described these wholly unexpected results at a few meetings during the 1950s, stirring curiosity among physicists and mathematicians. Meanwhile there were hints that such behavior was not confined to abstract mathematical systems. For example, a pair of scientists wrote a simple system of equations for the exchanges of carbon dioxide gas among the Earth’s atmosphere, oceans, and biosphere, and ran the equations through a computer. The computations tended to run away into self-sustaining oscillations. In the real world that would mean climate instability—or even fluctuations with no regularities at all.1 Nothing specific came of these and other peculiar results. It is not uncommon for scientists to turn up mildly anomalous calculations. They stick them away in the back of their minds until someone can explain what, if anything, it all has to do with the real world. The more people worked with computers, the more examples they found of oddly unstable results. Start two computations with exactly the same initial conditions, and they must always come to precisely the same conclusion. But make the slightest change in the fifth decimal place of some initial number, and as the machine cycled through thousands of arithmetic operations the difference might grow and grow, in the end giving a seriously different result. Of course people had long understood that a pencil balanced on its point could fall left or right depending on the tiniest difference in initial conditions, to say nothing of the quantum uncertainties. Scientists had always supposed that this kind of situation only arose under radically simplified circumstances, far from the stable balance of real-world systems like global climate. It was not until the 1950s, when people got digital machines that could do many series of huge computations, that a few began to wonder whether their surprising sensitivity pointed to some fundamental difficulty. At first the problem had seemed simply a matter of starting off with the right equations and numbers. That caught attention as early as 1922, when Lewis Fry Richardson published the results of a heroic attempt to compute by hand how a weather pattern developed over eight hours. His starting point was an observed pattern of winds and barometric pressure. Numerically simulating a day of development, Richardson’s numbers had veered off into something utterly unlike real weather. He thought his calculation would have worked out if only he could have begun with more accurate wind data. But as the meteorologist Carl-Gustav Rossby pointed out in 1956, people routinely made decent 24-hour predictions by looking at weather maps drawn from very primitive data. “The reasons for the failure of Richardson’s prognosis,” the puzzled Rossby concluded, “must therefore be more fundamental.”2
  • 10.
    Weart DGW 6/07Chaos - 5 magnified the wind data errors, which a human forecaster would have intuitively adjusted in gazing at the map. Worse, the process amplified the random sound waves that show up in the complete solution of equations for a fluid. See discussion by Lorenz (1967), p. 131; Norton and Suppe (2001), p. 93; for modern recalculation by P. Lynch, see Hayes (2001). 1 Levenson (1989), p. 89. 2 Norman Phillips, interview by T. Hollingsworth, W. Washington, J. Tribbia and A. Kasahara, Oct. 1989, p. 40, copies at National Center for Atmospheric Research, Boulder, CO, and AIP.. 3 C.E.P. Brooks quoted by Engel (1953); Nebeker (1995), p. 189. 4 Wexler (1956), p. 480. 5 Sutcliffe (1963), pp. 278-79. Instead of “external” he speaks of “extraneous” causes. The question of unstable computations was addressed most persistently by Philip Thompson, who had taken up weather prediction with the pioneering ENIAC computer group. In 1956, Thompson estimated that because of the way small irregularities got magnified as a computation went forward, it would never be possible to compute an accurate prediction of weather more than about two weeks ahead.1 Most scientists felt that all this resulted from the way computers chopped up reality into a simplified grid (and in fact some clever changes in the mathematics stabilized Phillips’s model). As another computer pioneer remarked, “meteorologists get so used to the idea that something bad is going to go wrong with their forecast that you’re not surprised” if a calculation couldn’t be made to work.2 The real world itself was presumably not so arbitrary. There had long been a few meteorologists, however, who felt that the atmosphere was so “delicately balanced” that a relatively minor perturbation could trigger not just a week’s storm, but a large and durable shift.3 In the 1950s, the idea was developed in speculative models of climate that showed abrupt variations, due to self-sustaining feedbacks involving factors such as snow cover. Support came from new data which suggested that climate conditions in the past had sometimes in reality jumped quite rapidly into a different state. The respected U.S. Weather Bureau leader, Harry Wexler, warned that “the human race is poised precariously on a thin climatic knife-edge.” If the global warming trend that seemed to be underway continued, it might trigger changes with “a crucial influence on the future of the human race.”4 The intellectual basis of the new viewpoint was well expressed in 1961 by R.C. Sutcliffe at an international climate conference. Using the popular new language of cybernetics, he described climate as a complex nonlinear feedback system. Unceasing variation might be “built-in,” an intrinsic feature of the climate system. Thus it might be pointless to look for external causes of climate change, such as solar variations or volcanic eruptions. Every season the pattern of the general circulation of the atmosphere was newly created, perhaps in a quite arbitrary way. The “sudden jumps” seen in the climate record, Sutcliffe concluded, are “suggestive of a system controlling its own evolution.”5 The father of cybernetics himself, mathematician Norbert Wiener, insisted that attempts to model the weather by crunching physics equations with computers, as if meteorology were an exact
  • 11.
    Weart DGW 6/07Chaos - 6 1 “self-amplification”: Wiener (1956a), p. 247, also warning that observations were “a very sketchy sampling of the true data.”; by “misleading” Wiener meant von Neumann and Charney. Jule Charney and Walter Munk, “Early History of Computing in Meteorology,” unpublished, copy from Arakawa’s papers kindly furnished by Paul Edwards, p. 9. See also Cressman (1996), p. 31. 2 “Dialogue between Phil Thompson and Ed Lorenz,” 31 July 1986, copies at National Center for Atmospheric Research, Boulder, CO,; Gleick (1987) 1295, pp. 11-18. science like astronomy, were doomed to fail. Quoting the old nursery rhyme that told how a kingdom was lost “for want of a nail” (which caused the loss of a horseshoe that kept a knight out of a crucial battle), Wiener warned that “the self-amplification of small details” would foil any attempt to predict weather. One pioneer in computer prediction recalled that Wiener went so far as to say privately that leaders of the work were “misleading the public by pretending that the atmosphere was predictable.”1 In 1961, an accident cast new light on the question. Luck in science comes to those in the right place and time with the right set of mind, and that was where Edward Lorenz stood. He was at the Massachusetts Institute of Technology, where development of computer models was in the air, and intellectually he was one of a new breed of professionals who were combining meteorology with mathematics. Lorenz had devised a simple computer model that produced impressive simulacra of weather patterns. One day he decided to repeat a computation in order to run it longer from a particular point. His computer worked things out to six decimal places, but to get a compact printout he had truncated the numbers, printing out only the first three digits. Lorenz entered these digits back into his computer. After a simulated month or so, the weather pattern diverged from the original result. A difference in the fourth decimal place was amplified in the thousands of arithmetic operations, spreading through the computation to bring a totally new outcome. “It was possible to plug the uncertainty into an actual equation,” Lorenz later recalled, “and watch the things grow, step by step.” Lorenz was astonished. While the problem of sensitivity to initial numbers was well known in abstract mathematics, and computer experts were familiar with the dangers of truncating numbers, he had expected his system to behave like real weather. The truncation errors in the fourth decimal place were tiny compared with any of a hundred minor factors that might nudge the temperature or wind speed from minute to minute. Lorenz had assumed that such variations could lead only to slightly different solutions for the equations, “recognizable as the same solution a month or a year afterwards... and it turned out to be quite different from this.” Storms appeared or disappeared from the weather forecasts as if by chance.2 Lorenz did not shove this into the back of his mind, but launched himself into a deep and original analysis. In 1963 he published a landmark investigation of the type of equations that might be
  • 12.
    Weart DGW 6/07Chaos - 7 1 Lorenz (1963), pp. 130, 141. This paper, now considered a classic, was not noticed by mathematicians for nearly a decade; like nearly all the stories in these essays, there is a lot more to this one, especially work by a number of other mathematicians. For additional details, see Dalmedico (2001). 2 His term for arbitrary was “aperiodic.” Lorenz (1964); Gleick (1987), pp. 21-31, 168- 169. 3 Lorenz (1968), quote p. 3; he described the randomness of a system of 26 equations (which was not very many for meteorology), published in Lorenz (1965); see also Kraus and Lorenz (1966); Lorenz (1970). 4 Mitchell said his printed “Concluding Remarks” were based on Roger Revelle’s summary at the conference itself. Mitchell (1968), pp. 157-58. used to predict daily weather. “All the solutions are found to be unstable,” he concluded. Therefore, “precise very-long-range forecasting would seem to be non-existent.”1 That did not necessarily apply to the climate system, which averaged over many states of weather. So Lorenz next constructed a simulacrum of climate in a simple mathematical model with some feedbacks, and ran it repeatedly through a computer with minor changes in the initial conditions. His initial plan was simply to compile statistics for the various ways his model climate diverged from its normal state. He wanted to check the validity of the procedures some meteorologists were promoting for long-range “statistical forecasting,” along the lines of the traditional idea that climate was an average over temporary variations. But he could not find any valid way to statistically combine the different computer results to predict a future state. It was impossible to prove that a “climate” existed at all, in the traditional sense of a stable long-term average. Like the fluid circulation in some of the dishpan experiments, it seemed that climate could shift in a completely arbitrary way.2 These ideas spread among climate scientists, especially at a landmark conference on “Causes of Climate Change” held in Boulder, Colorado in August 1965. Lorenz, invited to give the opening address, explained that the slightest change of initial conditions might randomly bring a huge change in the future climate. “Climate may or may not be deterministic,” he concluded. “We shall probably never know for sure.”3 Other meteorologists at the conference pored over new evidence that almost trivial astronomical shifts of the Earth’s orbit might have “triggered” past ice ages. Summing up a consensus at the end of the conference, leaders of the field agreed that minor and transitory changes in the past “may have sufficed to ‘flip’ the atmospheric circulation from one state to another.”4 These concerns were timely. Around the mid 1960s, many people were starting to worry about environmental change in general as something that could come arbitrarily and even catastrophically. This was connected with a growing recognition, in many fields of science and in the public mind as well, that the planet’s environment was a hugely complicated structure with points of vulnerability. Almost anything might be acutely sensitive to changes in anything else. So it was hopeless to look for comfortably regular weather cycles driven by single causes. The
  • 13.
    Weart DGW 6/07Chaos - 8 1 Wilson and Matthews (1971), p. 109. 2 Stringer (1972), pp. 300, 307-08; Federal Council for Science and Technology (1974); this is included as an appendix in United States Congress (95:1) (1977), p. iii; another review accepting continual and unpredictable change was Kutzbach (1976), p. 475. 3 In sum, “numerically small changes in climatic variables may produce significant environment changes,” Bryson (1974), pp. 753, 756, 759. 4 E.g., Newell (1974). 5 Lorenz (1970); as cited by Sellers (1973), p. 253. 6 GARP (1975), pp. 32-33. many forces that acted upon climate, all interacting with one another, added up to a system with an intrinsic tendency to vary, hard to distinguish from random fluctuation. A tentative endorsement of Lorenz’s ideas came in a comprehensive 1971 review of climate change. While the authors did not feel Lorenz had proved his case for certain, they found it “conceivable” that sensitivity to initial conditions “could be a ‘cause’ of climate change.”1 A typical textbook of the time spoke of the atmosphere as an overwhelmingly complex system of different “types of circulation” with rapid transitions among them. “The restlessness of the atmosphere sets a theoretical limit to its predictability,” the author concluded. That not only ruined any hope of forecasting weather beyond a week or so, but similarly hampered our ability to foresee climate change. A high-level panel on climate change agreed in 1974 that “we may very well discover that the behavior of the system is not inherently predictable.”2 In the early 1970s, concern about arbitrary climate change was redoubled by news reports of devastation from droughts in Africa and elsewhere. The most dramatic studies and warnings came from meteorologist Reid Bryson, who pointed out that the African drought had “minuscule causes,” which “suggests that our climate pattern is fragile rather than robust.”3 Meanwhile speculative new models suggested that a slight variation of external conditions could push the climate over an edge, plunging us from the current warmth into an ice age.4 Studies of dramatic past climate events added plausibility to these models. It was a short step to imagining a system so precariously balanced that it would go through self-sustaining fluctuations without any external trigger at all. As an author of one of the simple models put it, the results raised “the disturbing thought” that science could do no more than follow the history of climate as it evolved.5 Many meteorologists rejected this approach, what one prestigious panel called “the pessimistic null hypothesis that nothing is predictable.” After all, the entire program of the postwar physics- based revolution in meteorology aimed at prediction. Scientists holding to this ideal expected that gross changes could in principle be predicted, although perhaps not their timing and details.6 The task now was to determine where the limits of predictability lay. Theorists worked out mathematical arguments that showed how changes in climate could resemble a “random walk.” Perhaps the atmosphere was staggering like a drunkard among a multitude of possible states. Enough steps this way and that could add up to a large excursion, but in a random direction. If
  • 14.
    Weart DGW 6/07Chaos - 9 1 Hasselmann (1976). 2 Hays et al. (1976). 3 “orbital variations control the timing but not the amplitude.” Hays, Imbrie and Shackleton, reply to Evans and Freeland (1977), p. 530. 4 “stochastic” or “probabilistic” variability Mitchell (1976), p. 481. 5 Lorenz (1993), p. 120. 6 “Predictability: Does the flap of a butterfly’s wings...” was the title of an address by Lorenz to the American Association for the Advancement of Science, Washington, DC, Dec. 29, this picture was valid, then the places the drunken climate reached would be halfway predictable but never entirely so.1 The real world did follow a halfway predictable path, according to one interpretation of new field studies. In 1976, analysis of deep-sea cores revealed a prominent 100,000-year cycle in the ebb and flow of ice ages. That corresponded to a predictable astronomical cycle of variations in the Earth’s orbit. However, the cyclical changes of sunlight reaching the Earth seemed trivially small. The group of scientists who published the evidence thought the cycle of glacial periods must be almost self-sustaining, and the orbital changes only nudged it into the shifts between states.2 They called the variations in the Earth’s orbit the “pacemaker of the ice ages.” In other words, the astronomical cycle triggered the timing of the advance and retreat of ice sheets but was not itself the driving force.3 Without the timing set by this external stimulus, the ice cycles might wander without any pattern at all. Or changes could be set off arbitrarily with a nudge from any of various other forces that were easily as strong as the slight deviations of sunlight. Indeed the record showed, in addition to the main cycles, a great many fluctuations that looked entirely random and unrelated to orbital variations. Meanwhile, computer weather modelers were starting to admit they could find no way to circumvent Lorenz’s randomness. The new viewpoint was captured in a fine review by the leading meteorologist J. Murray Mitchell. He pointed out that climate is variable on all time-scales from days to millions of years. There were naturally many theories trying to explain this multifarious system, he said, and almost any given theory might partly explain some aspect. “It is likely that no one process will be found adequate to account for all the variability that is observed on any given time scale of variation.” Furthermore, the sheer randomness of things set a limit on how accurately scientists could predict future changes.4 Similar ideas were gradually becoming known to the entire scientific community and beyond under a new name—“chaos theory.”5 The magnification of tiny initial variations, and the unpredictable fluctuation among a few relatively stable states, were found to matter in many fields besides meteorology. Most people eventually heard some version of the question Lorenz asked at a 1979 meeting, “Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?” (Already in 1975 a science journalist had asked, “can I start an ice age by waving my arm?”) Lorenz’s answer—perhaps yes—became part of the common understanding of educated people.6
  • 15.
    Random documents withunrelated content Scribd suggests to you:
  • 16.
    chemicals kept theair purified, and earphones made communication possible. "Stand by for a landing!" Ripon's voice buzzed in the ear phones as Larry reported all hands ready. "We're going down!" The Sky Maid went down in a series of jerky drops. With eventual refinement, a ship equipped with the Ripon Magnetic Control would probably be able to come down as gently as a falling leaf, but this first apparatus was crude and experimental. Just at the end one of Ripon's elbows touched the wrong switch. The rocky surface swept up to meet them at high speed. He shouted hoarsely and spun compensating dials, but before he could check the momentum they struck with a heavy crash. The ship heeled over, and all the lights went out. As Larry was flung off his feet he heard a sharp hiss of escaping air. Momentarily half stunned, Larry lay on the floor in a corner of the control room with the body of another of the crew across his legs. Then he saw a bulky, space-suited figure heave to its feet across the room and heard Ripon's voice in his ear phones. "Leaping ray-blasts, what a crash! But I seem to be alive and in one piece. How about the rest of you?" Other men struggled to their feet and answered their names. One had his helmet smashed and was already dead in the airless atmosphere that remained after the air had rushed out through the shattered wall of the control room, but the rest had nothing more serious than a few bruises. "Well," Colton said. "Here we are! And here we're likely to stay." "It may not be that serious. The first thing is to take stock of our damage."
  • 17.
    The Sky Maid,they found on making a complete survey, was far less seriously damaged than might have been the case. The wall of the control room was punctured by a jagged splinter of rock, but there were only a few other minor leaks. Many of the compartments had retained their air. Once the hole was patched and the other leaks stopped, their reserve tanks still held enough air to let them make a homeward voyage in safety. The network of wires outside the hull would require considerable reconditioning, but none of the internal magnetic equipment was ruined. "About five days' work!" Ripon summed up. "And it's primarily a job for the engine room force. Gibson, Colton, the two quartermasters and I will go ashore with several days' supply of chemical capsules for the air conditioners on our helmets. Chief Engineer Masterson remains in command of the ship. Get her back in navigating shape as soon as you can, Chief." Masterson, a grimy and bullet-headed little man with a drooping mustache and something of the look of a mournful Airedale, slapped the side of his duro-glass helmet in a casual salute. Larry knew that the ship was being left in good hands. He had come to have considerable respect for the taciturn engineer. He did not know why Masterson was on board the Sky Maid, very likely because he had been in some trouble similar to Larry's own, but he was certainly an efficient engineer. He wished he felt as sure of the three men who were going ashore with Ripon and himself. Colton he considered thoroughly untrustworthy, and the two quartermasters were a pair of sullen derelicts of the sort that Ripon had picked up off the beach for most of the crew. "Landing party ashore!" Ripon snapped. "Let's get going! This isn't an ordinary exploring party, and every hour counts." VII
  • 18.
    They stood ona bare expanse of pitted rock. The Sky Maid had crashed on the outer slope of one of the craters, and the ground rose steadily to the jagged rim of the rocky bowl. Other bare peaks were all about them, black teeth against the starry sky. The earth gleamed large and pale above them. The scene was bleak and silent, unutterably desolate and forlorn, and the little group of Earthlings drew closer together. Then Ripon pointed up the ridge. "We'll go up there and look around. Larry—you carry the radium detector. We mustn't let the exploring fever make us forget our main purpose in having come here." They toiled slowly up the slope. Walking was difficult. Due to the power of their Earthly muscles on this planet of so much lighter gravity, they had a tendency to bound into the air at each step in spite of the heavy leaden soles on the feet of the space suits. Gradually they learned the necessary muscular control, a sort of sliding step, and then they made better progress. Ripon was some yards in the lead as they reached the rim of the crater. For a moment the tall scientist was silhouetted against the stars, then he abruptly dropped flat on the rock and motioned back to them to do the same. His voice was a faint whisper in the ear phones. "Crawl up here slowly, one at a time. Careful!" Larry was the first to join him, lying flat on the rock at Ripon's side. Together they peered down into the crater. It's flat floor was swarming with some sort of queer animal! This particular crater was a small one, and the level floor was only some thirty yards below the rim. Larry stared in amazement at the creatures who were coming to sit in long rows around a small mound in the center of the crater. He hardly knew whether to call them men or animals. They had the hard shell and articulated legs of an insect, but their faces had a semi-human appearance in spite of the pair of long antennae that grew out of their foreheads. Their feet made a dry rustling sound as they clambered down over the
  • 19.
    rock, and theycarried metal clubs with spiked heads. Larry saw that they walked with four of their six limbs while the upper pair were equipped with three curved fingers each. On the top of each antenna was a round ball that glowed with a phosphorescent light. "I thought there wasn't any life on the Moon!" Larry whispered. Ripon grinned at him through the duro-glass of his helmet. "You thought a lot of things that were wrong, young feller!" It was a weird scene in the cold pale light of the Earth. Some of the insect men came out of small, dome-shaped mounds that might have been houses. Others came climbing down the far side of the crater. Their glowing antennae bobbed in ceaseless motion, and there was a constant dry clicking. Suddenly Larry realized that the creatures were talking together! That meant that there was at least some atmosphere on the Moon! Enough to carry sound! Perhaps it had a different composition than the atmosphere of the Earth. It was certainly very thin, for the air in the control room had instantly escaped through the shattered side and the man with the broken helmet had smothered, but there was enough here to sustain these odd creatures. Then Ripon touched him on the arm, and Larry saw something that a group of the insect- men were very ceremoniously carrying to the mound in the center of the crater. It was an ordinary metal chair of a very common and familiar Earthly pattern, the sort of chair to be found in the cabins and mess rooms of any stratholiner. "One of those old ships must have reached the Moon after all!" Larry whispered. "That chair must be from the wreckage." "Heaven help the survivors if those many-legged devils got hold of them!" "They can't be very strong, with the Moon's gravity so slight," Larry said. "That doesn't prove a thing. They can be light in frame and still very strong. Think how many times his own weight our ant can carry, or
  • 20.
    how far aflea can jump." The chair had been placed in the center of the mound, and the Insect-men drew back. Now thin jets of steam or mist began to pour up around the mound, forming a foggy curtain that hid it. The mist only rose a little way, then dropped slowly down again to form an icy film on the cold rocks. The jets ceased, and mist vanished, and Larry Gibson stared in open-mouthed amazement. A dark-haired girl was standing erect on the crest of the mound! VIII The girl was white-skinned and lovely, utterly different from the grotesque creatures who surrounded her. Larry was crouching near enough to see her faintly smiling eyes, and the curve of her red lips, and the dark hair that fell to her waist behind. Except for the grotesque metallic helmet on her head, and the fact that she wore no clothing except for a silver loin cloth, she might have been a girl of the sort to be seen along the elevated cross-walks of New York City. "Do you see her too?" Ripon whispered. "I do." "We can't both be that crazy, so she must really be there. But how she breathes in that atmosphere, and how she avoids freezing to death, is more than I can tell you." The ceremony had evidently some sort of a religious significance, for the Insect-men were clicking rhythmically and were bowing down before the dark-haired girl. Goddess of the Moon! The girl's head- dress was a grotesque representation of an insect, set with jewels. At the tops of the flexible antennae were a pair of giant rubies. "Boy! Wouldn't I like to get my hands on those stones!" Colton whispered from where he crouched on Ripon's left.
  • 21.
    Then Larry noticedsomething else! A group of perhaps a hundred of the Insect-men were moving swiftly forward between the ranks of their bowing comrades. This group carried shields as well as clubs, and they had the purposeful air of men with a grim and serious errand to perform. The girl was staring over the heads of the crowd with a distant and goddess-like manner, and did not notice the newcomers till they had almost reached her. Then her eyes widened in alarm. She leaped up from her throne and burst into a torrent of shrill clicking. In an instant the crater was in a turmoil. The group of the heavily armed Insect-men charged straight for the mound in the center. Others flung themselves in their path, rallying to the defense of the Goddess. There was a wild flurry of swinging clubs. The spiked heads clanged on metal shields, or cracked sharply on the brittle brown shells of the Insect-men. The significance of the scene before him was still obscure to Larry, but it was evident that some kind of a revolt had broken out. The rebels among the Insect-men were outnumbered, but their metal shields gave them a big advantage and they were better organized. Like a spear-point they drove straight through the confused mass of worshipers and surrounded the low knoll in the center. They brushed its defenders aside and swarmed up toward the dark-haired Goddess. Larry had already drawn his ray-gun, but Ripon was the first to leap to his feet. "Come on, young feller!" he roared. "That girl is the first human thing we've seen on the Moon. We can't let her down. Let's show those many-legged devils how an Earth man can fight!" Larry and Ripon went down the slope of the crater in a series of bounding leaps. The milling Insect-men opened before them, seeming to welcome these unexpected reinforcements. Some of the rebels had already forced the struggling girl to her knees and were lashing her hands behind her back. A solid rank of them faced about with their round shields locked and a tossing fringe of spiked clubs waving atop the metal wall.
  • 22.
    The two Earthlingsdove for the shield-wall with their guns flashing. Larry ducked as one of the Insect-men hurled a club which just missed his glass helmet, then pressed the trigger of his ray-gun. The murky beam of the rays stabbed into the shield, melted a hole through it in a fraction of a second, and struck down the man behind. The flashing ray-guns of the two adventurers ripped the shield-wall asunder. A wave of the loyal Insect-men poured in behind them. Larry shifted his ray-gun to his left hand, and snatched up a fallen club with his right. It was heavier than he had expected, a well balanced and efficient weapon. The hard brown shells of the rebels cracked like china under the smashing blows of his Earthly muscles. Then he bounded up on the mound and struck down the pair of rebels who held the girl. Her wrists were now tied behind her. Throwing an arm about the girl's shoulders, Larry hastily faced about. Ripon was a few yards away. A ring of his slain lay around him, but his weapons had been knocked from his hands and he was struggling in the grip of a pair of the Insect-men. A third of the creatures was swinging a club to strike a blow at the scientist's glass helmet. Larry instantly fired, the beam of the ray striking the arm that held the club and shearing it clean off at the shoulder. A viscous yellow liquid dripped out, and the creature dropped writhing on the rock while it clicked in pain. Then Colton and the two quartermasters came charging belatedly up, and the fight was over. The crater was dotted with the still forms of dead Insect-men. Larry noticed that their hard shells gleamed dully in the dim light. The surviving rebels had fled off across the far rim of the crater, and the rest of the throng had gone chasing after them. No one remained in the crater except the strange girl and the party from the Sky Maid. When Larry had freed the girl's hands, she turned to the five Earth- men and touched her forehead in a gesture of thanks. Then she stepped across to touch some hidden spring on the far side of the
  • 23.
    mound, and atrap door opened in what had apparently been solid rock. The girl led the way down a narrow flight of stairs, motioning for the last man down to pull the trap closed behind them. They stood in a small chamber that had walls of roughly smoothed rock. It was evidently the work of men, for tool marks showed here and there. It was lighted by a green globe set in one wall. The globe appeared to be made of some kind of flexible glass, and it glowed with a faint greenish radiance that overcame the darkness enough to give the place a dim and eerie light. At one side of the room was an oval hole like a slanting well cut in the floor. Beside it stood a pile of low, flat carts. They were about two feet wide by four feet long, and they were supported on axles bearing small wheels the diameter of a man's hand. The girl spoke to Larry twice, first in the clicking talk of the Insect- men and then in some soft and musical tongue that was unlike anything Larry had ever heard. Both times he shook his head. Motioning for them to follow her, she put one of the low carts down near the rim of the hole and sat on it. Then she gave a push with her hands—and vanished. "Come on," Larry said, raking another of the carts. Colton stared at him. "Down that hole?" he asked. "Why not? We've got to find out what all this is about." A second later Larry Gibson found himself shooting down into the interior of the Moon by means of a sloping tunnel cut in the rock. A series of the greenish globes were set in the ceiling at intervals to give the rocky shaft a dim light. The wheels of the cart ran in two grooves cut in the floor, and he shot swiftly downward with a dull humming sound.
  • 24.
    Larry was tryingto estimate the speed of his downward movement. It was not so terribly fast, probably not really as fast as the nearness of the walls made it appear while they flashed by on either hand. The slope was a gentle one. Although he had gathered considerable momentum, he had no feeling of the car being out of control. As the minutes passed, Larry saw something else. The moisture that had been on the outside of his space suit from the air within the Sky Maid had frozen into a white frost a few seconds after the breaking of the control room wall let the outer cold into the ship. Now the frost was melting! They were getting into warmer regions as they went down. Perhaps they were also running into a heavier atmosphere! Larry held his hand up before him, and had a distinct feeling of pressure against it from the rush of air sweeping up to meet him. A minute later he had tested the atmosphere with the portable oxygen-gauge carried in the equipment pocket of any space suit. Then he took off his helmet. The air was quite warm, and though still very thin it was definitely breathable. Its clean, earthy odor was a pleasant contrast to the chemical product used over and over again inside the helmet of a space suit. A moment later he saw a brighter light ahead and realized that he had come to the bottom of the long shaft. They were in a square room whose walls were of polished gray stone. As Larry got up from his cart and moved in aside from the landing platform, the girl gave him a friendly smile. She had already taken off her ornately jeweled head-dress and placed it in a metal cabinet fastened to the wall. Completely without embarrassment, she tied a strip of gayly colored silk across her bare breasts. Then she tossed her long hair back from her forehead and bound another strip of silk to keep it in place. "That was quite a ride," Larry said. He had spoken in English, knowing that the girl would not understand but hoping the sound of the words would convey a generally friendly impression. She stared at him in startled surprise for a second.
  • 25.
    "It is muchpleasanter than the upward trip," she said at last. "But—but you spoke in English!" Larry gasped. "Why shouldn't I? My father is a man from Earth. I am Diana Staunton." IX As the others came sliding down into the room, Larry gave each one a formal introduction to Diana. The glow in the girl's eyes showed that she enjoyed their utter amazement. For a girl who had been born on the Moon, even though of Earthly parents, Diana Staunton had a great deal of poise and self-possession. "I am only a Goddess to the sluggish minds of the Insect-men," she explained in answer to Ripon's question. "To our own people of the Lost Caverns I am simply the daughter of one of the nobles." "I knew your father thirty years ago," Ripon said. "He has always told me that other men from Earth would come some day." "Your father can tell me most of the things I want to know, but I am wondering how you managed to survive up there on the surface where there is little or no air and it is always so cold." "I could not stay very long." From a fold in her loin cloth the girl drew out a tightly closed glass bottle that held some white tablets. "These contain oxygen mixed with some gases unknown on Earth, the whole very strongly compressed into solid form. Ten minutes after I swallow one, it is safe for me to go out on the surface. The effect lasts for about fifteen minutes." "Pretty risky if anything delays you," Larry said. Diana shrugged, and her blue eyes grew somber.
  • 26.
    "Someone has todo it. The loyalty of the Insect-men is our greatest protection against the evil Lords of Gral-Thala. This is the first time there has ever been anything like a revolt among the Insect-men. I do not know what lies behind it, but it probably means trouble for us of the Lost Caverns." Colton was the last to come down the rocky shaft. Larry noticed that the second officer was ill at ease, disinclined to meet his eyes, and wondered if Colton was ashamed of either his late entry into the fight or his fear of coming down into the Moon's interior. Hardly likely! From what he knew of Gerald Colton, the man was not likely to be ashamed of anything he did. They went through a maze of gray walled passages, still trending downward. Once or twice Larry thought he heard stealthy footsteps behind them, but there was no one in sight when he looked back. On several occasions they passed sentries wearing a makeshift armor, who saluted Diana with long bladed swords. Sometimes they spoke to her in English with a peculiar soft accent, sometimes in that strange tongue that Diana had first used. Larry noticed that these Lunarians looked only slightly different from the peoples of Earth. They had larger eyes, and a greater delicacy of feature. The principle distinguishing feature was their very thin legs. Often they had wide shoulders and deep chests, but since they did not need strong supporting muscles in view of the Moon's slight gravity their legs were thin and narrow. The sentries stared curiously at the Earth-men in their bulky space suits, but the fact that the newcomers were with Diana Staunton seemed to be sufficient passport. They began to pass a greater number of people in the corridors, and finally they stepped through a heavily guarded gate and came to a vast cavern. The place was huge, extending for a good mile ahead of them and with a lofty roof lost in the shadows overhead. Some of the gigantic columns that supported the roof were made of heavy stone blocks. Others were natural rock that had been smoothed and polished. All
  • 27.
    over the floorof the cavern were narrow streets, and small cottages built of some queer composition that came in a rainbow of different colors, and little patches of some sort of green grass. A golden and rather misty light pervaded the whole cavern. Square shafts of a brighter radiance darted down from above at irregular intervals, and wherever one of them struck the floor of the cavern there was a small patch of cultivated ground with long-leafed plants. "Agriculture by chemical control!" Ripon whispered in Larry's ear. Diana glanced back at them over her shoulder. "This is Chotan, largest of the Lost Caverns," she said. "The Council of Elders is now in session, and it will be best that we go direct to them." "Why do you call these the Lost Caverns?" Larry asked. "Because we who live here are outlaws, and the location of these vast caves is not known to the Lords of Gral-Thala who rule the other side of the Moon." "Apparently not all the inhabitants of the Moon are so friendly," Ripon said. "If you came into the hands of the Lords of Gral-Thala," she said grimly, "they would tear the skin from your bodies and use it to lace their scented golden boots!" Large-eyed Lunarians stared curiously at the Earth-men as they hurried through the streets of the underground village. Diana led them direct to a broad-beamed, red-roofed building that stood by itself in the center of the cavern. A dozen elderly men sat behind a long table of carved wood that was black and cracked with age. It was, Larry realized, the first wooden thing he had seen since he landed on the Moon. At either side of the chamber stood a squad of armored warriors. Larry was staring at a curious device that was carved in the center of the table, and carried on a banner hung above the heads of the council, and inlaid in a white metal on the bluish steel shields of the
  • 28.
    guards. And thenhe recognized it! It was the crescent Earth, the profile of the mother planet as seen from the Moon when the Americas were still in sunlight and the shadows of night were creeping across the Atlantic. The sight of it made him home-sick. The crescent moon had been a religious symbol to many of the ancient races of Earth, and it was fitting that the crescent earth should hold a similar place on this isolated satellite. It seemed to Larry that Diana was a trifle nervous over something. She had entered the council chamber with an air of confidence, lifting one arm in a stately gesture of greeting and asking the Elders to accept the men from Earth as friends and guests, but he sensed a degree of uncertainty behind her manner. In hasty phrases she told the council of the revolt of part of the Insect-men, and of the timely arrival of the strangers from the mother planet. "And so I request that you accept these men into the Brotherhood of the Caverns!" she finished. The graybeards behind the long table nodded gravely, but before they could speak another voice rang but in a sharp challenge. "And I, O Elders of Chotan, demand that these interlopers be put to death in accordance with the ancient law of the Caverns concerning unwanted strangers!" X The speaker was a fair-haired young man in a green cloak. He looked more like an Earthling than a Lunarian, with his sturdy legs and small eyes. He pointed an accusing finger straight at Larry in a dramatic gesture, and Diana wheeled to face him with anger in her voice. "You talk very loudly of the ancient laws, Xylon, for a newcomer only recently taken into the Brotherhood because you fled as an outlaw from the Lords of Gral-Thala!"
  • 29.
    "I did notmake the laws!" Xylon retorted. "The death penalty for strangers has not been strictly enforced for many years—or you would not now be alive! It is up to the decision of the Elders!" The council chamber was in an uproar, with shouted phrases flung back and forth. Larry laid a hand on the butt of his ray-gun. A keen- eyed officer of the guards caught the gesture, and instantly Larry found a pair of rifles directed at his chest. At least, they looked like some sort of compressed air rifles. They had fiber stocks, and long barrels, and a cylindrical magazine beneath the barrel. Then a deep voice dominated the tumult as a red-haired man in full armor forced his way through to the forefront of the crowd. "The girl is right, O Elders and members of the Brotherhood!" he boomed. "Xylon talks like a fool. I, Pyatt of Kagan, urge that the strangers from Earth be accepted. Let Xylon remain among us for a little while longer before he attempts to dominate our councils!" Larry could sense the swing of sentiment in their favor, could feel the lessening of the tension. The man called Xylon shrugged and turned away. Then the council took a formal vote, waving the ancient death penalty and allowing the strangers the freedom of the Caverns. One of the Elders near the end of the table rose to his feet. He wore the typical black robes of the Council, but as Larry looked closely at the man's lined face he saw the resemblance to Diana and knew that he was looking at Lester Staunton. "Since these men are from what was once my own land," Staunton said, "I will make them comfortable in my house for the duration of their stay here." As the crowd began to stream out of the council-chamber, the red- headed man pushed his way through to Ripon and Larry. He was unusually burly and big-thewed for a Lunarian, and though his face was marred by a pair of old scars he had a wide and cheerful smile. "Welcome to the Cavern of Chotan!" he boomed. "I am Pyatt of Kagan, military commander of all the armed forces of the Caverns.
  • 30.
    Later I willwant to talk to you about that revolt of the Insect-men, which is something that has not happened before. Also, we will drink a goblet of wine together." "Then you have wines on the Moon?" Ripon asked, visibly brightening. "Aye, wines of many sorts. Though my own taste runs more to the strong-waters that fire the blood and set a man's head to spinning." "I can see that you and I have a lot in common!" Ripon grinned. Just before they left, Xylon came up to shake hands with Larry. "No hard feelings, Earthling!" he said. "It is just that the safety and liberties of the Caverns are very precious to one like myself, who has so recently become an outlaw, and I did not think that we should take any chances." "That's all right," Larry said shortly. Now that he saw Xylon at really close range, he realized that the man was older than he had thought. His appearance of youth vanished when you saw the many fine wrinkles in his face and the weariness around his eyes. He had a dissolute appearance. Xylon might be sincere in his bid for friendship, but Larry felt that there was something serpentine and evil about the man. With Diana and her father and a few others, they walked along one of the many winding paths of Chotan. Larry noticed that the chemically grown plants had no scent at all. The motionless, warm air was suffused with a misty and golden light. Small, neat houses built in various bright colors stood amid their plots of grass. It was a strange scene to Earthly eyes, that cavern far below the Moon's chill surface, but it was a pleasant spot in its way. The women they passed along the walks were dressed like Diana, in a gayly colored loin-cloth with a narrow band across the breasts.
  • 31.
    Most of themen wore a loose, colored cloak in addition to the single garment. Only a few were armed. Larry had taken off the right mitten of his space suit to shake hands with Pyatt and Xylon in the council chamber. Several times he had started to replace the mitten, but something had always distracted him and he was still carrying it in his left hand. Now, as he happened to give the mitten a shake, a small insect of a blood-red color fell out and landed on the walk. It looked something like a miniature scorpion. Larry had only a hasty glimpse before Pyatt of Kagan leaped forward and crushed the crawling thing with the heavy sole of his sandal. "That was a spanto!" he said. "Their bite means death within ten seconds. I wonder how it came to be in your glove!" "I wonder myself!" Larry said grimly, looking across the field at the green-cloaked figure of Xylon, who had turned off on another of the branching walks. It would not have been hard for Xylon to have dropped the insect in his glove! As if in answer to his thought, Diana spoke quietly: "I do not trust Xylon any farther than I can see him, friend Larry! There is something unclean in his eyes when he looks at me." "If he looks at you too much while I'm here I'll break his jaw!" Larry said. The girl looked up at him with a sudden smile that was also a challenge. "I begin to understand why my father has always said that I would like the men from Earth better than the Lunarians!" XI They sat in Professor Staunton's laboratory, a square chamber where Earthly equipment taken from the wreck of his space-ship was mingled with typically Lunarian furniture and equipment. The walls
  • 32.
    were light blue,of that polished composition resembling bakelite that was used for building in the Caverns. The walls were about ten feet high, and they ended in an ornamental cornice without any ceiling or roof at all. Overhead there was a glow of misty light, and far above the rocky top of the cavern. "Why should we need roofs?" Diana said in reply to Larry's surprised comment. "Here in these Caverns there is neither rain nor snow nor wind, nor any change in temperature at all. The walls give privacy, and there is no need for anything else." Ripon was bending over a table on which Staunton had spread a large map of the Moon. The cavern of Chotan was indicated by a red dot, and Larry saw that there were a dozen others scattered around within a radius of a few hundred miles. "Our space-cruiser was wrecked near one of the entrances to this cavern when we landed here thirty years ago," Staunton said. "As you have guessed, it was the inability to land safely with rockets, in a practically airless atmosphere where helicopters were useless, that smashed us. As you did, we had fortunately put on space suits before trying to land. Our ship was too badly wrecked for any chance of return." "But how have you succeeded in getting all these people to learn English?" Ripon asked. "They knew that language before I came! But it is best that I give you a hasty outline of Lunarian history. The simple-minded but husky Insect-men were the aboriginal inhabitants of the Moon. Long æons ago, while most of the people of Earth were living crudely in caves and using chipped stones for tools and weapons, an isolated people developed a high civilization in what I have roughly identified as the region of the Himalayas. A series of great earthquakes destroyed their civilization, but a large number of them escaped and came to the Moon in some kind of a space-ship. Here they found, in those days, a small planetary body that had a thin but breathable air. They founded a civilization on the other side of the Moon where it is
  • 33.
    always sunny, andcalled it Gral-Thala. Those were pleasant days, if the old legends are to be believed, the Golden Age of Lunarian civilization." For a moment Staunton paused. All those in the room, including the Lunarians who had been familiar with this tale since childhood, hung intently on his words. The broad face of Pyatt of Kagan was somber and moody as he sat bent forward with the scabbard of his sword resting across his armored knees. "As the centuries passed, the atmosphere continued to thin," Staunton went on, "so the Ancients took care to preserve what was left. Gral-Thala is in the fertile part of the Moon, and lies in a vast valley completely surrounded by a lofty mountain range. By means of the superior engineering knowledge of the Ancients, they built a lofty wall or barrier along the crest of the range so that its top is miles above the level of the valley floor. They then sucked all the air within the Great Barrier. Gral-Thala itself thus lies in a great pool of air surrounded by the ranges and the barrier. On the rest of the Moon, as here, air only remains in deep crevices and caverns like this." "But these caves were a great labor in themselves..." Ripon began. "Originally these caverns were built as outposts of Gral-Thala, built here because of their nearness to valuable mineral deposits. People came out from the sunlit cities within the Great Barrier to put in a tour of duty in the caverns. Again life on the Moon had reached a pleasant equilibrium. And then came the great disaster! Some two centuries ago a group of several hundred outlaws fleeing from Earth came here in a big space-ship." "The Mercury!" Larry exclaimed. "Exactly. Those men and women who came from Earth were few in comparison to the population of the Moon, but they were cruel and
  • 34.
    ruthless and theyhad weapons of war. The peaceful Lunarians had at that time no weapons at all, for they had no need for them. Within a few months the invaders made themselves Lords of all Gral- Thala! That was when English, the language of the invaders, came to be spoken by everybody on the Moon as well as the softer tongue of the Lunarians themselves. A few of the hardier folk in Gral-Thala fled to these caverns as outlaws. The invaders made only half- hearted attempts to come after them, and with the passing of the years the location of these refuges has been forgotten by people living within the Great Barrier. That is why these places are now known as the Lost Caverns." "And the invaders still rule?" "Their descendants are still Lords of Gral-Thala. Cruel and ruthless they always were, decadent and dissolute they have now become as well, but they still rule the sunny valley that was the pride of the ancient Lunarians. They hold the power, and they are aided by a few groups among the people of Gral-Thala who have sacrificed their honor to fawn upon their masters. Our spies, who penetrate beyond the barrier, tell us that before long there will come a day when the people are ready for revolt—but the time is not yet." "But surely!" said Pyatt of Kagan, his deep voice breaking in on the low monotone in which Staunton had spoken, "surely our visitors will return to Earth, now that interplanetary travel has become possible, and bring us the warriors and equipment to storm the high palaces of the tyrants of Gral-Thala!" "I should think that the Confederation of Earth would send help, particularly since the original invaders were outlaws from that planet," Staunton said. "How about it, friend Ripon? How are conditions back on Earth at this time?" Ripon straightened up and shook his shoulders. The glow in his eyes faded away, and the lines in his face deepened once more. "The Lunarians can look for no help from Earth until one thing is accomplished," he said. "I have been letting scientific enthusiasm
  • 35.
    make me losesight of our reason for coming here. How are conditions on Earth, you ask? I can tell you in a single sentence. Unless we of Earth very quickly get a new supply of radium salts suitable for use with the Riesling Method, in a few weeks we all perish!" "I do not understand." In a few hasty phrases Ripon sketched the development of the terrible plague that was so swiftly robbing Earth of its inhabitants. At the end Staunton leaned back in his chair. "Such salts are available on the Moon in ample quantity," he said slowly, and something in the quality of his voice robbed the words of the reassurance they would otherwise have held, "but—they are all located well within the area of the Great Barrier. And the Lords of Gral-Thala would never let you have even a single milligram!" "Then there's only one thing to be done!" Larry stood up and began to peel off his space suit. "If someone will show me the way, I'll go into Gral-Thala and bring out as much of the radiatron extract as I can carry." "And I will go with you!" boomed Pyatt of Kagan. "By Gorton and Laila, mythical gods of the Moon, it will take more than a few of those cold-eyed tyrants to stop us!" XII Time was the thing that counted. The remorseless pressure of minutes and hours that passed and could never be recalled! The tyrants who lorded it over Gral-Thala had no weapons more deadly than the electronic guns that had been common on Earth two hundred years before. A battalion of troops from Earth, wearing armor of dura-steel and carrying ray-guns, could probably have overthrown the Invaders very quickly. But—there was no time! The
  • 36.
    toll of theGray Death was increasing with each passing hour, back there on the Good Green Planet, and the little group on the Moon would have to do what they could without hope of assistance. They could not pause for proper preparations or careful planning. It was only half an Earth day after they had landed on the Moon, time enough to snatch a few hours' sleep, that Larry found himself moving up toward the surface in a slowly crawling cable car. Chotan already lay behind and far below them, and the oxygen indicator fastened to the sleeve of the space suit showed him that the air was thinning rapidly. Colton and Pyatt were with him. All three of them wore space suits of the Lunarian patterns, that had a metal helmet with glass windows at the front and sides, for the difference in design of the space suits from the Sky Maid would have made them too conspicuous. Pyatt had come along because he had often penetrated beyond the Great Barrier in disguise, and a second Lunarian was waiting for them up on the surface. Ripon had also wanted to come, the idea of this daring raid setting the old, reckless light danging in his eyes. Finally he agreed that one of the leaders of the Sky Maid expedition had better remain in the Caverns in case of disaster to the raiders. "That's the hell of getting along in years, young feller!" he rumbled regretfully. "There's nothing I'd like better than to penetrate the barrier with you and pull the whiskers off the tyrants in their lair. A quick wit and a ready weapon! But I couldn't keep up with you younger men if the going gets hot—though I never thought the day would come when I'd hear Crispin Gillingwater Ripon admit a thing like that!—and you'd better go on without me." "We'll be back soon," Larry said. Ripon snorted. "If you're not back in five days I'm coming after you with the crew of the Sky Maid and as many of the folk of the Caverns as I can get to come along!"
  • 37.
    The Cavern ofChotan was in that part of the Moon which is sometimes in sunlight and sometimes in darkness, and it was night when they came out of the tunnel. The moisture on the space suit instantly froze into a fine white frost. A few Lunarian sentries waited for them there, and nearly a hundred of the Insect-men. With them were two carts that had high wheels and springs, something like an old-fashioned Earthly buckboard. For a few moments, Pyatt talked to the leaders of the Insect-men in their clicking tongue. The glowing knobs atop their antennae bobbed up and down as they nodded their heads in understanding. Then Pyatt motioned Colton into one of the carts and climbed in beside him. Another Lunarian, slender even in the bulky space suit, climbed into the second cart beside Larry. Pyatt swung his right arm forward. A score of the Insect-men instantly scampered ahead as scouts, spreading out like the spokes of a fan. Small parties went out to either flank. The rest, about thirty to each cart, gripped the trailing ropes and darted ahead with the wagons following behind them. They went at almost incredible speed, the four legs of each giving them a steady drive. Even though the Insect-men were picking the smooth stretches of the rock and were evidently following a definite though unmarked trail, it was rough going. The light wagons jolted and banged as they whizzed along, and Larry had to cling to the rail with both hands to keep from being thrown off. "Is all the way as rough as this?" he panted to his companion. "Better soon," the Lunarian said shortly. After about three hours they turned into a smooth and level road. It wound up and down over the rolling rocky plain, evidently a highway of great age. Occasionally they passed crumbling ruins beside it. Larry supposed that the road and the ruins dated back to those very
  • 38.
    ancient days beforethe Lunarians withdrew their shrinking supply of air within the Great Barrier. Now that the road was smooth, the Insect-men pulled the carts along at a whizzing pace. The light wheels whirred as the wagons shot ahead. The scene, Larry reflected, was like a nightmare. All about him were the chill mountains and craters of the Moon, lifting their jagged peaks against the cold stars. Ahead of the speeding wagon ran the toiling cluster of Insect-men, their hard shells gleaming faintly in the starlight and their glowing antennae bobbing in a swift rhythm as they ran. The treads of the wheels rattled on the rocky surface of the road, the horny feet of the Insect-men made a steady scraping sound as they ran. The two men seated in the cart ahead were monstrous and misshapen figures in their space suits. Larry's companion had remained sullenly silent, in spite of several efforts to start a conversation. This was unusual in one of the normally pleasant and talkative Lunarians, but Larry had not thought much about it. Now, as he made some remark about the speed of their progress, he heard a low chuckle and in his earphones sounded the voice of Diana Staunton. "Yes, Larry, we travel fast. In a few days we will enter the zone of sunlight." "You," he exclaimed. "This expedition is too dangerous. I would never have let you come if I had known." "Why else do you think I kept so silent until now, when it is too late to send me back?" she asked, and though he could not see her face through the glass of her helmet in the darkness he could tell that she was smiling. "Neither would Pyatt of Kagan or my father have let me come. I stole the space suit of the young man who was to accompany you and left him locked in a storeroom." "You will have to remain outside when we go within the barrier." "Where you go, I go," she said with finality.
  • 39.
    Sunrise on theMoon! There was no sudden onslaught of light as on the Earth, for the Moon day was twenty-eight days long! Yet, as they progressed steadily toward the horizon, the Moon's rotation brought the edge of the sun gradually into sight above the barren horizon, and as the days passed, a blinding glare of light swept in upon them and they moved the dark glasses into place in front of the windows of their space-suit helmets. The temperature rose rapidly with the coming of the two weeks' sunlight, and before long the frost on the space suits was melting. Then, stretching along the crest of a mighty mountain range ahead, Larry saw a lofty gray wall that went so high its top was almost lost from view above. They had come within sight of the Great Barrier! XIII Several times along the way they had been halted by sentry-patrols from some of the other outlaw caverns, who warned them that an unusual number of strong parties of troops from Gral-Thala were roaming the waste-land. However, they came without incident to a tiny outlaw hide-out. This was within half a mile of one of the caverns that was under the domination of the Lords of Gral-Thala. Two hours later Larry and the others stood with a score of other people, in an air-lock in a great tunnel that led through the mountain range and into Gral-Thala. All these people were residents of the valley returning from a tour of duty in the caverns, and the four outlaws from Chotan had been furnished with forged documents that gave them the same identity. The space suits had been removed and hung on numbered racks. The three men wore the tight tunics and loose trousers that were the customary dress within the valley, as distinguished from the loin
  • 40.
    cloth and cloakof the cavern outlaws. This was fortunate, for the trousers concealed the sturdy Earthly legs of Larry and Colton which would have stood out in sharp contrast to the typical spindly shanks of the otherwise well-built Lunarians. Diana wore a loose robe, with tight wrappings concealing her hair and a thin veil over her face. A heavy guard of soldiers checked the papers of all the travelers before they let them through. These troops wore light armor, and each carried an electronic gun slung from his shoulder. The officers were evidently of the Invaders, cruel-eyed men cast in the same mold as Xylon. The men were Lunarians, generally of a rather debased type and drawn from among the worst element in the population. A heavy-featured trooper glanced at Larry's papers in a perfunctory manner, then handed them back. "All right, all right!" he growled. "Get along. Don't block the way!" The tunnel ended on the inner slope of the mountain range surrounding Gral-Thala, where many cars ran down the steep incline into the city below. It was a pleasant and smiling land that Larry Gibson saw before him, a sunlit and fertile valley so vast that even the lofty range on the far side was invisible over the horizon. Towns and villages dotted the plain. Farms lay among their fertile fields. A small river wound through the center. Directly below him, clustered against this part of the valley wall, was a mighty city. "This is the city of Pandonaria," Diana's voice came softly through her veil, "capital city of Gral-Thala." The city itself was a terraced mass of colored buildings cut by many streets and interspersed with gardens. Several towering palaces of white and gold, the abodes of the Lords of Gral-Thala, dominated the lower buildings. It was good to see real sunlight again! To see birds flying overhead! To smell the odor of flowers and growing things, in contrast to the flat and motionless air of the Lost Caverns! It was hard to believe that this pleasant spot was really the scene of such a brutal tyranny as he had been told. Then they rounded a bend in the sloping road and came to an abrupt halt.
  • 41.
    At the sideof the road stood a sort of gallows, made of strips of a ruddy metal bolted together. From it hung the nude body of a young Lunarian girl. She was suspended by her bound wrists high above her head, and her feet swung far off the ground. From the clotted blood at her bound wrists, and the way the eternal sun of the valley had burned her skin, Larry knew that she had hung there many hours. The girl was far gone but she was not yet dead. At intervals her drooping head moved feebly from side to side. A pair of armored soldiers leaned on their weapons below the gallows. Around the girl's neck hung a sign, lettered in the archaic English script that was the official language of Gral-Thala: "THIS GIRL DARED STRIKE ONE OF THE NOBLES OF GRAL-THALA WHO CONDESCENDED TO NOTICE HER." Fierce anger filled Larry Gibson's heart, a consuming anger that set his clenched fists shaking. For some reason he thought of Diana. Though she stood only a few feet away from him, he visioned her hanging from such a gallows if the dissolute tyrants of this land ever stormed the Lost Caverns. Then Pyatt of Kagan laid a hand on his arm. "Careful, my friend!" the Lunarian hissed. "Your anger shows on your face, and that is bad. We cannot help that poor girl now. Come!" They went down into the city, avoiding the broad boulevards and keeping to the narrower streets where the poorer people were. As they passed by the base of one of the high palaces, they came to the body of a girl who lay crushed on the stones and had evidently been thrown or jumped from one of the upper windows. An aged man stood astride the body, leaning back and shaking his skinny fists at the white and gold bulk of the palace above him. "Woe be upon the Lords of Gral-Thala!" he screamed in his shrill old voice. "Triple woe upon the tyrants and upon the decadent parasites who fawn upon them. Evil lies in wait for ye, lurking in your white
  • 42.
    palaces with yourguards and your harlots! The hour of doom is not far away! The vengeance of Gorton and Laila may be long delayed, but it comes in the end! Woe to the Lords of Gral-Thala!" An uneasy, sullen, murmuring crowd was gathered around the ragged old man although they left a broad circle of vacant space around him and the body of his granddaughter. A few troopers of the garrison were making a half-hearted effort to push the crowd back. They were uncomfortable in the face of the unspoken but obvious hatred of the throng. Larry and the others prudently kept to the back of the crowd. Even so, they were near enough to see what happened next. Silver bells rang sharply, and lackeys called an arrogant summons to clear the way. In the midst of a circle of armed guards, porters carried a swaying gilt litter. On the cushions of the litter rested a man. It was one of the nobles of Gral-Thala, a perfumed degenerate in silken robes with a rouged and painted face. For a moment he stared at the crowds with his arrogantly scornful eyes. Then, as he saw the old man beside the girl's body and heard the curses he was shouting, his patrician face was distorted into a sneering frown. The noble snarled an order, and one of his guards lifted his electronic rifle. There was a flash of blinding light! A sudden clap of miniature thunder, and a smell of ozone. The man-made lightning bolt struck the old man in the chest and knocked him sprawling across the body of his granddaughter. With a faint smile the noble leaned back on the cushions of the litter and waved languidly to his porters to move on again. "Let us go, my friends!" Pyatt whispered hoarsely. "We cannot right all the wrongs of Gral-Thala at one stroke, and our mission is the most important thing at the moment." XIV
  • 43.
    They were walkingslowly down one of the quiet streets of the city, a quarter where there were few guards and little chance of discovery. Larry noticed that all the windows were equipped with heavy shutters, so that the light could be closed out when the inhabitants of this land desired to sleep. It was a place of unending daylight, always turned toward the sun, where darkness never came. Colton was more interested in the metal rails that ran along the walks on the outside of the buildings. "My Lord!" he said softly, "These are gold!" "Of course," Pyatt of Kagan said absently, "Gold is one of the most common metals in Gral-Thala. Our problem is the matter of the radium salts. I happen to know that they are stored in small boxes made of ura-lead, in one of the government storehouses. It would be easier to steal some direct from the mines, but there is no time for that because of the question of proper packing and handling. We must risk everything on a bold attempt to raid the warehouses." "Suits me," Larry said quietly. Just then Diana gripped him by the arm and jerked him back against the wall of the nearest building. "Look there!" she hissed. Another litter was passing along the cross street just ahead of them. This litter went in evident haste, with lackeys swinging whips to clear the path and the passenger bending forward to urge his bearers to greater haste. The man who rode in the litter was Xylon! The four outlaws stared at each other in grim and ominous surprise. There had been no doubt of the identity of the man who had just passed within a few yards of them. "But what does that mean?" Larry gasped. "It means that I have been a fool!" Pyatt snarled. "Xylon is evidently no outlaw who came to the caverns to seek shelter, but a spy sent out by the Lords of Gral-Thala. Now I understand the reason for that revolt among the Insect-men! He must have stirred it up in an attempt to kidnap Diana here because of her hold over those simple
  • 44.
    creatures. Now thelocation of the Lost Caverns is at last known to the tyrants, and there will be an attack in force." "And Xylon knows that we are here in Pandonaria!" Diana exclaimed. "Which means that all our lives hang by a thread no heavier than a woman's hair! We must get under cover at once! Then we will send word back to the Caverns by secret radio, that they may prepare for an assault. After that we will plan an attempt on the radium salts." The outlaws of the Lost Caverns had certain confederates within the city, and they now took refuge in the house of a small merchant who was a distant cousin of Pyatt. Larry watched as Pyatt and the merchant crouched over the sending set concealed in a small closet built in the thickness of one of the walls, the arkon-bulbs flashing as they sent the warning to Chotan to be spread to the other caverns. At last Pyatt straightened up. "At least that is done," he said. "Now we will wait two hours, which will be the time of the Third Meal. There will be few people on the streets, and the warehouse guards will be drowsy, and we will have our best chance." Pyatt and Colton had gone somewhere else in the house, and Larry sat with Diana in a small room whose windows looked out on the green fields beyond the city. The girl had loosened her blue veil so that it hung in soft folds about her chin. "This is the first time in my life I have been anywhere but in the Caverns and on the waste-land," she said moodily. "This valley of Gral-Thala is a pleasant place." "You would like Earth even better." "I suppose I would. Will you take me back to that Earth of yours when you return, Larry?"
  • 45.
    "Not until theGray Death is overcome! I would not want to take any chance of it striking you down." "Do you love me, Larry?" she asked, without either coquetry or embarrassment. "I guess I do. Of course, we've only known each other for a few hours—but I guess I do." "I am glad," she said simply. The two hours passed, and Pyatt came striding back into the room. They had given him one of the ray-guns brought ashore from the Sky Maid, and he carried it thrust in his girdle close to his hand. "It is time to go," he said. "We must make our attempt now, win or lose. Where is Colton?" "I thought he was with you." "Haven't seen him in two hours!" A hasty search of the merchant's house and small grounds revealed no trace of the missing officer. Pyatt stood glowering blackly and pulling at his chin. "I don't like it," he said. "Yet, if the soldiers had taken him, they would have come for us as well." A different thought was running through Larry's mind, a grim and unpleasant suspicion. He was remembering Colton's past history ... his general sullenness ... the greed that he had shown throughout the entire expedition. He was also remembering that he had seen Colton in deep conversation with Xylon a few hours before they had left Chotan. "I am afraid," he said bitterly, "that Colton has sold us out to Xylon and the Lords of Gral-Thala for promise of reward. We had better get out of this house right away, before...." Larry never finished that sentence. There was a roaring crash, and the door was shattered by the impact of a pair of electronic bolts
  • 46.
    fired by thesoldiers who had crept up to the house. Armored figures came pouring in the door! Others were at the back. Pyatt of Kagan, fighting furiously, went down under press of numbers. Larry managed to get his ray-gun up and fire one blast that crumpled a charging trooper in mid stride, but then half a dozen gripped him and the brief fight was over. They were taken! XV The hands of the three prisoners were tied behind their backs, and nooses were placed around their necks. Then they were dragged out into the street. The merchant was not taken prisoner at all, simply killed out of hand with the body left lying across his shattered threshold. A thin-lipped, hooked-nosed officer spat in Larry's face as he was led past the body of the dead merchant. "Not for you will there be such an easy ending," he sneered. "An example is to be made. You will die before crowds, in the Plaza of the Four Virgins, and the process will be a slow one." They were surrounded by a double rank of guards as they were led along by the nooses about their necks. All three had been stripped to a loin cloth, and the sun was scorching hot upon Larry's back and shoulders. At least, he thought thankfully, Diana's long black hair gave her some protection. There were jeers and hoots as they were led through the crowded streets, but most of them came from members of the tyrant class and from the few over-dressed and foppish Lunarians who aped their masters. The mass of the people gazed in stony and somehow sympathetic silence. Into one of the tall white-and-gold palaces of the Lords of Gral-Thala they were taken, and down into stone-walled dungeons far underground. They were placed in a single cell. They stood with their backs against the walls, arms out-stretched and wrists lashed
  • 47.
    to rings setin the stone, able to move little more but their heads. Then, for a while, they were left alone. "Well," said Larry with grim humor, "here we are." "So it seems!" Pyatt's voice was rasping and bitter. "I am indeed a fool for ever having allowed Xylon to live in the Cavern of Chotan, in spite of the kind-hearted ruling of the Elders." "What will they do with us?" Larry asked. Pyatt hesitated, licking his lips and glancing at Diana, but the girl answered for herself. "We shall probably be skinned alive in the public square, dying slowly under the torture," she said. "It is the favorite punishment of the tyrants for those they particularly hate." It was a day of triumph for the Lords of Gral-Thala. Xylon's triumphant return with the information that would lead to the wiping out of the always troublesome outlaws of the Lost Caverns, and the capture of the three prisoners, made it a holiday for the ruling class of the valley. They came in hundreds to see the three captives. The famous military leader of the outlaws ... the girl who was considered a goddess by the primitive Insect-men of the waste-land ... the the stranger from that distant Earth whence their own ancestors had fled. They came to throng the dungeon corridor and stare in at the trio of captives spread-eagled against the wall of the cell. Larry watched them through the barred door. For hours on end there were always a few of them in the corridor, staring and jeering. Foppish men in white and gold with their curled hair laden with scent. Haughty and jewel-clad women whose sharp featured faces held even more cruelty than their male companions. Many were attended by Lunarian slave girls whose fettered hands held their trains up from the floor, and the bare backs of the slave girls were usually marked with the crossing red marks of whips. Larry knew, now, that the tales told in the Caverns about the cruelty of the Lords of Gral-Thala had not been exaggerated.
  • 48.
    Xylon came tosee them after a while, opening the cell door and walking in to stand sneering at them with his thumbs hooked in his jeweled girdle. "Colton sold you out for the promise of wealth and a place in the ranks of our nobles," he said. "It will be a pleasure to watch you die." For a moment he walked over to stand in front of Diana who looked back at him with an expressionless face. "You are not a bad- looking wench. I can take you for one of my slaves if you wish to be agreeable." "I would rather go with an Insect-man!" the girl said with calm scorn. Xylon shrugged and turned away. "So be it. At that, it would be a pity to rob the crowd of the pleasure of watching you die." As near as Larry could judge it, the equivalent of an Earthly day had passed before they were taken out of the cell. They were given an hour to ease their stiffened muscles. Then the guards bound their wrists before them, and by the trailing ends of the ropes led them out of the dungeons and through the streets to a broad open space just at the foot of the inclines that led down from the tunnel by which they had entered the city. The Plaza of the Four Virgins, named from the four gigantic statues of polished stone that had been placed at its corners in some long ago day before the Invaders came, was a vast paved space in front of an ancient temple that was now used as a government building. In front of the temple a metal scaffold had been erected with two heavy uprights and a cross-piece. The rulers of Gral-Thala were sprawled in cushioned ease on the steps of the temple, well guarded by their troops, and the floor of the Plaza was filled with the common people of the city. These latter were present in great number, a silent and ominously sullen mass. The three prisoners were stood in a row on the scaffold. Their hands were raised above their heads, and the ropes made fast to the cross- piece so that they were held tautly erect and motionless. Sharp
  • 49.
    Welcome to ourwebsite – the ideal destination for book lovers and knowledge seekers. With a mission to inspire endlessly, we offer a vast collection of books, ranging from classic literary works to specialized publications, self-development books, and children's literature. Each book is a new journey of discovery, expanding knowledge and enriching the soul of the reade Our website is not just a platform for buying books, but a bridge connecting readers to the timeless values of culture and wisdom. With an elegant, user-friendly interface and an intelligent search system, we are committed to providing a quick and convenient shopping experience. Additionally, our special promotions and home delivery services ensure that you save time and fully enjoy the joy of reading. Let us accompany you on the journey of exploring knowledge and personal growth! ebookultra.com