Page:Popular Science Monthly Volume 17.djvu/185

Rh rainy to an unusually vigorous movement of the Gulf Stream, in consequence of an exceptional pressure of the southeast trade-winds, which he claims produced an extensive diffusion of Gulf vapor in a northerly direction, greatly mitigating the winds in the United States. Others attribute these effects to a change in the condition of the sun, which during the last year is said to have been in a state of repose that is very rare, there being no spots or eruptions visible upon its surface. The latter theorists maintain that, when the sun-spots are at the greatest height, or at their maximum, the earth receives the greatest quantity of heat; and that, when the spots are at the lowest, or their minimum, the heat is proportionately lessened. Others, however, dispute this altogether, declaring that the observations that have been made of the maximum periods of the spots on the sun's surface do not coincide, over any length of time, with the warm and cold years, and do not, therefore, justify any such inference. Monsieur de Perville, on the other hand, maintains, as the result of long observations of dry and rainy seasons in Europe, that they correspond with known changes of the moon. In connection with which I may mention, as a curious fact, derived from recent Assyrian researches, that the Babylonians and Chaldeans attributed changes in the weather to the influence of the moon, and kept up a system of regular observations of the moon for practical purposes.

The extreme dryness and consequent want of moisture for the fertilization of the fields in parts of India and China, hitherto fruitful and thickly populated, is attributed to the wanton destruction of the forests on the hillsides. In 1879 Mr. Hilliard visited the famine stricken province of Shang-Si, in China, and found in these famine districts that the trees had been extensively destroyed, and attributes the want of moisture and the consequent infertility of the soil to this cause. Observations made in France by M. Mathieu and by M. Fautral over a period of four years, by different methods, as to the effect under trees and the effect in treeless plains, led to the same general results, which are as follows: That it rains more abundantly over forests than over open ground, especially when the trees are in leaf; that the air above the forest is more saturated with moisture than over the open ground; that the leaves of trees intercept one third, and, in some trees, half of the rainfall, and that the leaves and branches restrain the evaporation of the water which reaches the ground, moistening the earth four times as much as it is moistened by the rain that falls upon open plains.

Geographical inquiries are not limited to the discovery of unknown countries or places, but embrace the discovery of the remains of lost civilizations or cities, one of which has been discovered during the last two years. The readers of the Bible will remember the frequent mention that is made of the Hittites, a people occupying Canaan, who are described in the Biblical narrative as being commercial and military,