In examining the literature of this subject it was found that the experience in other countries could not be used as a guide in considering our problems. In general, irrigation in Europe and Asia is practiced only to supply deficiencies, and the crops there raised are only in part the same as with us, and the variation on account of the crops is very great. Certain statements of Marsh in his “Man and Nature” have been copied into the journals and reports published in the United States, and made to do duty on many occasions; but these statements are rather misleading, as the experience of farmers in the Arid Region has abundantly demonstrated. The writers who have used them have in general overestimated the quantitative value of water in irrigation. The facts in Italy, in Spain, in Grenada, and India are valuable severally for discussion in the countries named, but must be used in a discussion of the arid lands of the United States with much care. It seemed better, under these circumstances, to determine the quantitative value of water in irrigation in Utah from the experience of the farmers of Utah. Irrigation has there been practiced for about thirty years, and gradually during that time the area of land thus redeemed has been increased, until at present about 325,000 acres of land are under cultivation. A great variety of crops have been cultivated--corn, wheat, oats, rye, garden vegetables, orchard trees, fruits, vines, etc., etc.; and even the fig tree and sugar cane are there raised. During the past six or seven years I have from time to time, as occasion was afforded, directed my attention to this problem, but being exceedingly complex, a very wide range of facts must be considered in order to obtain a reasonably approximate average. During the past year the task of more thoroughly investigating this subject was delegated to Mr. Gilbert. The results of his studies appear in a foregoing chapter, written by him; but it may be stated here that he has reached the conclusion that a continuous flow of one cubic foot of water per second, _i. e._, a _second-foot_ of water, will, in most of the lands of Utah, serve about 100 acres for the general average of crops cultivated in that country; but to secure that amount of service from the water very careful and economic methods of irrigation must be practiced. At present, there are few instances where such economic methods are used. In general, there is a great wastage, due to badly constructed canals, from which the water either percolates away or breaks away from time to time; due, also, to too rapid flow, and also to an excessive use of the water, as there is a tendency among the farmers to irrigate too frequently and too copiously, errors corrected only by long experience. The studies of Mr. Gilbert, under the circumstances, were quite thorough, and his conclusions accord with my own, derived from a more desultory but longer study of the subject.