Sir C. Scott Moncrief, in his address as president of the engineering section of the British Association for the Advancement of Science, describes the various forms of irrigation. The primitive method consists in raising water by human labor. Early Egyptian sculpture depicts laborers raising water by means of buckets, and along the banks of the Nile the same method may be seen to-day. Other methods of raising water are by pumps driven by windmills. In certain regions Artesian wells furnish water for irrigation. The importance of irrigation is best shown in the fact, that, while the rainfall in Cairo is, on an average, one and four tenths inches a year, yet in the immediate neighborhood land brings $750 per acre; this value being due to irrigation alone. In speaking of water storage for supplying the irrigating canals the author says: "When there is no moderating lake, a river fed by a glacier has a precious source of supply. The hotter the weather the more rapidly will the ice melt, and this is just when irrigation is most wanted." (Judging from this dictum, the condition in Mars is ideal.) In speaking of the great Assouan Reservoir in Egypt, he says: "The sale value of land irrigated by its waters will be increased by about $125,000,000. The increase in irrigation areas in our Western States may be appreciated by the following figures. In 1889 it amounted to 3,564,416 acres; in 1900, to 7,539,545 acres. Now it is at least 10,000,000 acres. Without irrigation this land sold for four or five dollars per acre; with irrigation it brings forty dollars per acre. XIII VARIETY OF CONDITIONS UNDER WHICH LIFE EXISTS _Not only does life but intelligence flourish on this globe under a great variety of conditions, as regards temperature and surroundings, and no sound reason can be shown why under certain conditions which are frequent in the universe, intelligent beings should not acquire the highest development._ SIMON NEWCOMB.