7O LANDS OF THE ARID REGION OF THE UNITED STATES. 
consecutive decades. District I comprises the sea coast from Maine to 
Virginia, and the record includes five or more stations from 1827 to 1867. 
From the decade 183140 to the decade 184150 the rainfall increased 
6 per cent. District II comprises the state of New York and adjacent 
regions, and includes five or more stations from 1830 to 1866. Irom the 
decade 184756 to the decade 185766 the rainfall increased 9 per cent. 
District IV comprises the Ohio Valley and adjacent regions, and includes 
five or more stations from 1837 to 1866. From decade 1841—50 to decade 
1851-60 the rainfall diminished 8 per cent. 
The case, then, stands that the best comparable districts and epochs 
exhibit extreme fluctuations from decade to decade of from 6 to 9 per cent, 
while the rise of Great Salt Lake implies a fluctuation of about 10 per 
cent. But before deciding that the hypothetical fluctuation in Utah is 
extraordinary, consideration should be given to the fact that in the dry 
climate of that region a given change in humidity will produce a relatively 
great change in rainfall, while an identical change of rainfall, measured in 
inches, acquires an exaggerated importance when expressed as the percent- 
age of a small total rainfall. Giving due weight to these considerations, 
I am led to conclude that the assumed increase of rainfall in Utah is not 
of incredible magnitude, and consequently that the hypothesis which 
ascribes the rise of the lake to a change of climate should be regarded as 
tenable. It by no means follows that it is proven, and so long as it depends 
on an assumption the truth of which is merely possible, but not established, 
it can claim no more than a provisional acceptance. 
It is proper to add that, so far as I entertain the idea of a change of 
climate, I do so without referring the change to any local cause. It is 
frequently asserted that the cultivated lands of Utah ‘draw the rain”; or 
that the prayers of the religious community inhabiting the territory have 
brought water to their growing crops; or that the telegraph wires and 
iron rails which gird the country have in some way caused electricity to 
induce precipitation; but none of these agencies seem to be competent. 
The weather of the globe is a complex whole, each part of which reacts on 
every other, and each part of which depends on every other. The weather 
of Utah is an interdependent part of the whole, and cannot be referred to its 
