The climate of a great land area not only finds expression in its fauna and flora, but in the industries and the intellectual development of its people. While it is difficult to translate man's physical and intellectual development into terms of climate, it is evident that the transition province favours both bodily and mental activity more than any of the other climatic provinces into which North America is here divided. Although the boundary between the upper austral and the transition provinces is indefinite, it is easily to be seen, from the geographical distribution of cities, agricultural population, manufactories, colleges, and other institutions of learning, etc., that the climate of the province under review is on the whole the one in which the greatest intellectual advance has been made and the one which holds out the greatest promise for the future. _The Boreal Province_ (Plate III).--This climatic division of North America extends in a broad belt diagonally across the continent from the eastern portion of Labrador nearly to the shore of Bering Sea, and is represented by detached areas in both the Atlantic and Pacific mountains far beyond its general southern limit. Its northern border, in the Continental basin, is marked by the cessation of forests, and on the mountains to the southward its upper limit coincides with the timber-line. Its leading climatic features are its low mean annual temperature--in general from 32 deg. to 40 deg. F.--its long, cold winters, and short, hot summers. The differences in mean annual precipitation in various parts of the province are less marked than in the several provinces previously noticed, but in the far north a cold arid division should be recognised. Although but few direct measures of precipitation are available for comparison, our general knowledge of the great boreal province and the character of its vegetation indicate that there is a decrease in precipitation from both the eastern and western borders of the continent towards the interior, and also from its central portion both northward and southward. The heaviest precipitation is on the Pacific coast, from California northward to southern Alaska, and the lightest precipitation is probably in the central Continental basin, near the northern limit of the province. Precipitation on the Pacific coast at low elevations is almost entirely in the form of rain, but on the mountains there is in winter deep snow which remains for a number of months unmelted. Throughout the portion of the province included in Canada and Alaska the snowfall is abundant, but heaviest towards the Atlantic coast. Along the northern margin of the province, as indicated by observations at a small number of stations, not only is the mean annual precipitation light, probably under 20 inches, but the winter snow is not deep, although it remains on the ground continuously for five or six months. In the main or northern portion of the boreal