METEOROLOGY, 331 
GENERAL CONCLUSIONS. 
The favorable conclusions as to the climate of the country in the route of the expedition, 
stated in the first report, have been fully sustained by more recent observations. 
As shown by the accounts of all who have traversed the Rocky mountains, during almost 
every winter month the snow there met with would not present the slightest impediment to the 
constant passage of railroad trains. And, in regard to temperature, the whole of these mountains 
between Fort Benton and Bitter Root valley, a distance in a straight line of 190 miles, have a 
milder winter climate than Wisconsin or Iowa, or any part of Nebraska east of the 100th 
meridian. A mean temperature of 20° to 25° must prevail throughout, excepting about five 
miles of the dividing ridge, which, rising 2,500 feet above the Bitter Root valley, and 3,400 
above Fort Benton, will, by the rule already stated, fall to a mean of 16°; though from its very 
narrow extent, and the almost constant influence of the west winds, it must usually approach 
nearer the climate of Bitter Root valley, or have a mean of 19°.5. Even when crossed by 
Lieutenant Grover, while the cold northeast wind was blowing, we find that its temperature 
was more than a degree higher than it should have been when compared with Fort Benton. 
From the increasing altitude and width of the Rocky mountain plateau, towards the south 
we find that the length of country, having a climate of similar coldness, must be much greater, 
as traversed by any line of railroad between this and that of the 35th parallel; while there, the 
distance from the mild winds of the Pacific coast, and the local influences of a much greater 
extent of snowy mountains, must still further decrease the mean winter temperature. The 
increased mildness of winter, due to a more southern latitude, is more than compensated by 
the greater altitude of any pass between the two routes; while the same fact is to be seen in 
relation to any interval of the same length (190 miles) traversed by the routes through those 
passes. 
Of the relations of climate to the agricultural capacities of the country on the route, enough 
has been given to show that, while inferior to many parts of the United States in = adaptation 
for great variety of crops, it compares favorably with the best portions of the empire of "uns 
for the cultivation of the great staples of agriculture, and west of the Rocky mountains far 
surpasses them, approaching the most productive countries of Europe ш character. Compared 
with any other route north of the 30th parallel, the climate is superior for Mee». : The 
natural growth of trees among the mountains, on this route alone, provos the superiority of 
climate over that of the elevated portions of the central Rocky mountains, where there is not 
sufficient moisture to sustain them, except at a higher elevation, varying from 5,000 to 8, 000 
feet. There is nothing in the soil of any portion, except the western part of the great plain 
of the Columbia, which forbids agriculture; and, allowing for mountains also, the distance 
traversed through lands, not cultivated continuously, will not exceed 320 as a maximum, most 
of which is grazing land, and contains patches pe arable land sufficient for a stock-raising 
populatior, and for nuclei for mail and railroad stations. 
