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Meteorology; or Weather Explained

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<h2>CHAPTER XXXIII</h2> CLIMATE One is not far up in years, in Scotland at any rate, without practically realising what climate means. He may not be able to put it in words, but easterly haars, chilling rimes, drizzling mists, dagging fogs, and soddening rains speak eloquently to him of the meaning of climate. Climate is an expression for the conditions of a district with regard to temperature, and its influence on the health of animals and plants. The sun is the great source of heat, and when its rays are nearly perpendicular—as at the Tropics—the heat is greater on the earth than when the slanted rays are gradually cooled in their passage. As one passes to a higher level, he feels the air colder, until he reaches the fluctuating snow-line that marks perpetual snow. The temperature of the atmosphere also depends upon the radiation from the earth. Heat is quite differently radiated from a long stretch of sand, a dense forest, and a wide breadth of water. Strange is it that a newly ploughed field absorbs and radiates more heat than an open lea. The equable temperature of the sea-water has an influence on coast towns. The Gulf Stream, from the Gulf of Mexico, heats the ocean on to the west coast of Britain, and mellows the climate there. The rainfall of a district has a telling effect on the climate. Boggy land produces a deleterious climate, if not malaria. Over the world, generally, the prevailing winds are grand regulators of the climate in the distinctive districts. A wooded valley—like the greatest in Britain, Strathmore—has a health-invigorating power: what a calamity it is, then, that so many extensive woods, destroyed by the awful hurricane twelve years ago, are not replanted! Some people can stand with impunity any climate; their “leather lungs” cannot be touched by extremes of temperature; but ordinary mortals are mere puppets in the hands of the goddess climate. Hence health-resorts are munificently got up, and splendidly patronised by people of means. The poor, fortunately, have been successful in the struggle for existence, by innate hardiness, otherwise they would have had a bad chance without ready cash for purchasing health. It may look ludicrous at first sight, but it seems none the less true, that the variation of the spots on the sun have something to do with climate, even to the produce of the fields. On close examination, with a proper instrument, the disc of the sun is found to be here and there studded with dark spots. These vary in size and position day after day. They always make their first appearance on the same side of the sun, they travel across it in about fourteen days, and then they disappear on the other side. There is a great difference in the number of spots visible from time to time; indeed, there is what is called the minimum period, when none are seen for weeks together, and a maximum period, when more are seen than at any other time. The interval between two maximum periods of sun-spots is about eleven years. This is a very important fact, which has wonderful coincidences in the varied economy of nature. Kirchhoff has shown, by means of the spectroscope, that the temperature of a sun-spot must be lower than that of the remainder of the solar surface. As we must get less heat from the sun when it is covered with spots than when there are none, it may be considered a variable star, with a period of eleven years. Balfour Stewart and Lockyer have shown that this period is in some way connected with the action of the planets on the photosphere. As we have already mentioned, the variations of the magnetic needle have a period of the same length, its greatest variations occurring when there are most sun-spots. Auroræ, and the currents of electricity which traverse the earth’s surface, follow the same law. This remarkable coincidence set men a-thinking. Can the varying condition of the sun exert any influences upon terrestrial affairs? Is it connected with the variation of rainfall, the temperature and pressure of the atmosphere, and the frequency of storms? Has the regular periodicity of eleven years in the sun-spots no effect upon climate and agricultural produce? Mr. F. Chambers, of Bombay, has taken great trouble to strike, as far as possible, a connection between the recurring eleven years of sun-spots and the variation of grain prices. He arranged the years from 1783 to 1882 in nine groups of eleven years; and, from an examination of his tables, we find that there is a decided tendency for high prices to recur at more or less regular intervals of about eleven years, and a similar tendency for low prices. An occasional slight difference can be accounted for by some abnormal cause, as war or famine. Amid all the apparently irregular fluctuations of the yearly prices, there is in every one of the ten provinces of India a periodical rise and fall of prices once every eleven years, corresponding to the regular variation which takes place in the number of sun-spots during the same period. If it were possible to obtain statistics to show the actual out-turn of the crops each year, the eleven yearly variations calculated therefrom might reasonably correspond with the sun-spot variations even more closely than do the price variations. This is a remarkable coincidence, if nothing more. What if it were yet possible to predict the variations of prices in the coming sun-spot cycle? Such a power would be of immense service. By its aid it could be predicted that, as the present period of low prices has followed the last maximum of sun-spots, which was in the year 1904, it will not last much longer, but that prices must gradually keep rising for the next five years. Could science really predict this, it would be studied by many and blessed by more. Yet the strange coincidence of a century’s observations renders the conclusions not only possible, but to some extent probable.     <hr style="width: 50%;" /> <div style="break-after:column;"></div>

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