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 percentage 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 causes until the entire subject is mastered. The simpler and more immediate meteoric reactions have been so far analyzed that their results are daily predicted; but the remote sources of our daily changes, as well as the causes of the greater cycles of change, are still beyond our reach. Although withdrawn from the domain of the unknowable, they remain within that of the unknown. THEORY OF HUMAN AGENCIES.