METEOROLOGY. 399 
wave of temperature towers up under the influence of a vertical sun and cloudless sky, it sinks 
proportionately low during the night, rendering it cool and chilly.” The range of difference 
is there sometimes 41° in July, and the mean range for that month 929,1. Тһе range for the 
three summer months is 19°.6 or 79°.7 for the greatest heat by day, and 60°.8 for the 
mean coldest hour of the night. This evidently arises from the fact that the more the air is 
rarefied and ascends by day, the more cold air from the neighboring snowy mountains must 
rush down to take its place at night, until, as in August, even that of the mountains becomes 
so heated that the minimum range of 16°.3 is reached. His table is the result of two years’ 
observations. The range will be less in direct ratio to the distance of any given place from 
the snowy or lofty mountains. It is probably, also, less where, as in this Territory, the greatest 
heat by day differs least from the mean, or from the mean temperature of the neighboring 
mountains. 
One of the greatest agricultural advantages of the climate near the Pacific coast is in the 
earlier commencement of spring and later coming of winter, which makes the growing season at 
least a month longer, and prevents the droughts of summer from seriously interfering with 
cultivation. 
This fact is shown to exist by the comparison of the means for the three winter months, as 
already made in the tables of climate in places of similar annual temperature. It is also well 
known to characterize and influence materially the processes of agriculture in California and 
elsewhere. To demonstrate its application to the region now under consideration I give a table 
of comparison of February, March, and December, with places already used in this connexion : 
February. March. December, 
о о о 
Bitter Root valley, means of two years 30.7 бақ ut 
Rochester, New York, 24 years 26.4 iod "s 
Detroit, Michigan, 13 years 26.6 н i a : 
Beloit, Wisconsin, 6 years "a id ue 
Fort Snelling, Minnesota, 353 years : : : n : my 
Fort Benton, Nebraska, 1 year . . : 
Lapwai 24 years 38.8 42.7 40. 
? 
қ 34.5 42.7 38.6 
Pa re oe 40.0 46.4 33.7 
Dalles, 6 years "n 5 40.8 33.0 
Ven uin 36.3 45. 6 37.1 
Philadelphia, 20 years эм aee ia 
epe =~ ae : 35.0 44.0 33.6 
- Louis, 23 years .... 
34.1 43.5 34,5 
Cincinnati, 20 years 
We thus find that cultivation may be commenced some days earlier in the Territory p. at 
places several degrees further south in the Atlantic States, and some weeks — — inp es 
of the same latitude. Allowing for the close vicinity XN all the желмін — >> : 
mountain ranges, we may suppose that a still greater difference s in pes " ex че 
the Great Plain, where the greater dryness of summer also requires an early cultiva e 
success, The difference will be at once apparent, to farmers especially, as a mean wee ede 
below 32° prevents ploughing in winter and various other operations, and stops entirely t 
428 
