GEOLOGICAL SURVEY OF THE TERRITORIES. 261 



from the bed of the stream, below this water would commence issuing 

 from the porous soil. So large is this supply in some instances, that 

 the amount due to percolation in the Jumna is estimated at one thou- 

 sand eight hundred and sixty cubic feet per second, while the total 

 ■ amount at the canal heads is placed at but three thousand four hundred 

 and ninety cubic feet ; showing a restoration by percolation of over fifty 

 per cent. The same thing has been observed in Northern Italy. M. 

 Lombardini states that the Ticino at Tornavento, the Adda at Cassano, 

 and the Oglio at Torre Pallavina, in times of great dryness, are entirely 

 closed and exhausted. Yet, without the aid of any visible affluent 

 whatever, the streams soon reappear, formed by new supplies derived 

 from percolation through the banks and springs in the beds, so that 

 they early again become navigable. 



While it is not probable this would be the case at that distance out 

 upon the Plains where the streams now begin to sink, yet there is noth- 

 ing to forbid the presumption that it would occur nearer the mountains 

 and along those streams which have their sources in the snowy ranges. 

 But it is necessary to study carefully all these points before the agricul- 

 tural capacity of the great West can be known. 



In my estimates of the heights which might be reached by irrigating 

 ditches I have confined myself to the rule generally adopted in the 

 West, of giving to them a descent of from three to five feet to the mile. 

 But the longitudinal slope of the Ganges Canal varies from twelve to 

 fifteen inches ; and the larger canals in Italy generally have a descent 

 of from seventeen to twenty -four inches to the mile. 



LAND GRANTS. 



It may not be improper for me to say something in respect to the in- 

 fluence of land grants upon agriculture in this part of the West. 



While 1 believe that the laws granting homesteads to actual settlers 

 are wise and proper, and should not be abridged, yet I do not think 

 that a fear of encroaching upon them should prevent such judicious 

 grants in that section as would have a tendency to develop it. I am 

 no advocate for the indiscriminate granting of land all over our country 

 wherever asked for. But where there is a section which cannot be de- 

 veloped without some aid of this kind, then it is wise in the Government 

 to bring it into use, if every foot of the soil be required to do it. The 

 question in such places is reduced to this one point : Shall the soil for- 

 ever remain idle and valueless, or shall it be brought into use by giving 

 portions of it for its redemption. % 



As remarked in the introduction, there are facts and principles which 

 hold good in the rain-moistened sections which entirely fail in the West. 

 In the former each quarter-section can be brought under cultivation 

 without any other preparation than clearing it of timber, save the 

 swamps and rugged mountains. But in the latter water must be 

 brought to the lands by means of ditches and canals, which, as in the 

 case of the higher levels and broader plains, often costs an outlay of 

 thousands of dollars. Hence combination or capital is necessary, in 

 order to do this at a reasonable cost per acre. The immediate bottoms 

 of the streams can and will be brought into use chiefly by individual 

 efforts, as here each farm can have its own acequia at a moderate ex- 

 pense. But these compose only a small proportion of the lands that are 

 susceptible of irrigation and culture. The greater part of the remainder 

 will require ditches or canals varying from five to fifty or more miles in 

 length, yet by making these of proper dimensions and taking in as large 



