"It isn't regular at all," the Weather Forecaster explained. "If climatic conditions were regular, we could forecast the weather several years in advance, instead of only a few days. There are a thousand complicating factors. Land and sea are irregularly divided, and as there is more evaporation from the sea than the land, every little curve in a coast line means a disturbance of regularity. Then, Anton, remember, while the earth is almost a globe it is not perfectly round, so that every variation from the regular curve disturbs the air currents. Moreover, the motions of the earth are very complicated. Sometimes it is nearer the sun than at other times. It wobbles slightly on its axis. It is inclined to the plane of the ecliptic, causing the seasons, and that brings a new set of factors into the problem. A mountain range or a desert will modify the atmosphere, even the difference between a forest and a prairie is noticeable." "Suppose you could figure all those things out, couldn't you foretell the weather, then?" The Forecaster shook his head. "Suppose you had a thousand marbles of different colors," he said, "and you dropped them from the top of a house to the hard ground below, a rough and rocky piece of ground, could you ever figure out what kind of a pattern they would make? You might measure the size of the marbles and compute how many times they would strike against each other in falling, meantime figuring the angles of direction that each collision would produce. You might measure the resistance of the ground and the elasticity of the marbles and estimate the manner in which they would bounce after striking the ground and the distance to which they would roll. After you had done all that, you might have the right to expect that you would know the pattern that the marbles would make as they lay scattered on the ground. But you would be wrong, for if you dropped those marbles a thousand, yes, a million times, the pattern would be different each time. After tens of billions of experiments you might be able to find the proportion of patterns, but the result would never be of practical use. "It's the same way with the weather. We know well enough how to do the things that would enable us to prophesy a long time in advance what the weather is going to be, but the problem approaches impossibility because there are too many factors that enter into the calculation. We're learning all the time, but it's a big piece of work and needs big men to do it. That's why, Anton, I can't tell you why this particular district had more rain this year than it has had for several seasons past." Anton, pegging away on his crutch beside the Forecaster, looked up at him with an added eagerness in his eyes. "And yet all those things are going on, right where I can see them!" he exclaimed.