Page:Oregon Historical Quarterly volume 12.djvu/288

 280 CHARLES WILKES The mean height of the barometer during our stay at Nis- qually was 30.046 inches, and of the thermometer 66 58' F. The greatest heat was 98 F. at 2 p. m. July 4, and at 4 a. m. of the same day it was 50 F. The lowest degree was 39 at 4am. May 22, and at 5 p. m. of the same day the temperature was 72 F. From June to September at Vancouver the mean height of the barometer was 30.32 inches and of the thermometer 66 33' F. Out of 160 days 96 were fair, 19 cloudy, and 11 rainy. The rains are light. This is evident from the hills not being washed, but having a sward to their top although at great declivity. The second or middle section is subject to droughts; during the summer the atmosphere is much dryer and warmer, and the winter much colder than in the western section. Its extremes of heat and cold are more frequent and greater, the mercury at times falling as low as 18 F. in the winter and rising to 108 F. in the shade in the summer, and a daily difference of temperature of about 40 F. It has been, however, found ex- tremely salubrious, possessing a pure and healthy air. The stations of the missionaries and posts of the Hudson Bay Co. have afforded me the means of obtaining information rela- tive to the climate; although they have not kept full data, yet their observations afford a tolerably good knowledge of the weather. In summer it is cooled by the strong westerly breezes to re- place the vacuum produced by the heated prairie grounds. No dew falls in this section. The climate of the third or easterly section is extremely variable ; the temperature during the day, ranging from 50 to 60, renders it unfit for agriculture, and there are but few places in its northern part where the climate would not effect- ually put a stop to its ever becoming settled. In each day, from the best account, one has all the changes incident to spring, summer, autumn, and winter. There are places where small farms might be located, but they are few in number.