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. CHAPTER XXXIV THE "CHALLENGER" WEATHER REPORTS The _Challenger_ Expedition, commenced by Sir Wyville Thomson, and after his death continued by Sir John Murray, with an able staff of assistants for the several departments, was one of the splendid exceptions to the ordinary British Government stinginess in the furtherance of science. The results of the Expedition were printed in a great number of very handsome volumes at the expense of the Government. And the valuable deductions from the _Challenger's_ Weather Reports by Dr. Alex. Buchan, in his "Atmospheric Circulation," have thrown considerable light upon oceanic weather phenomena. For some of his matured opinions on these, I am here much indebted to him. Humboldt, in 1817, published a treatise on "Isothermal Lines," which initiated a fresh line for the study of atmospheric phenomena. An isotherm is an imaginary line on the earth's surface, passing through places having a corresponding temperature either throughout the year or at any particular period. An isobar is an imaginary line on the earth's surface, connecting places at which the mean height of the barometer at sea-level is the same. To isobars, as well as to isotherms, Dr. Buchan has devoted considerable attention. In 1868, he published an important series of charts containing these, with arrows for prevailing winds over the earth for the months of the year. In this way what are called synoptic charts were established.