166 



SCIENCE. 



[Vol. IV., No. 82. 



IRRIGATION IN THE UPPER MISSOURI 

 AND YELLOWSTONE VALLEYS. 



In crossing the great plains over the Union 

 Pacific railroad, through Nebraska and Wyo- 

 ming, or over the Kansas division through Kan- 

 sas and Colorado, one is struck not only by 

 the aridity of the country, but also by the fact 

 that no streams of water exist there, adequate, 

 if completely utilized, to irrigate any consider- 

 able part of that immense area. One is also 

 struck by the monotony of the physical fea- 

 tures, the absence of mountains or hilly areas, 

 as well as of timber. The possibility of set- 

 tling this vast region seems very remote ; and 

 only the discovery of some new and as } r et 

 untried method can prevent these plains from 

 constituting, for ages to come, the great natural 

 barrier between the east and the west, — a bar- 

 rier far more complete than that furnished by 

 the Rocky Mountains themselves. 



This condition exists to a greater or less ex- 

 tent as we go southward, though the direction 

 of this belt of uninhabitable country lies some- 

 what to the west of south. Before I had seen 

 Dakota or Montana, I feared, when reflecting 

 upon these facts, that such a belt might extend 

 northward also, and thus, as it were, actually 

 divide the United States into two sections, 

 marked off from each other by a permanent 

 physical obstruction. This problem seemed 

 to me of the utmost importance, for it is the 

 remote future that must be considered ; and if 

 the country has proved capable of so nearly 

 dividing upon an east-and-west line, where 

 there does not exist a single natural feature 

 to render the two sections distinct, what might 

 not be apprehended at some future day, when 

 sectional differences arise between the east and 

 the west, if cut off from each other by an unin- 

 habited desert five hundred miles in width ? 



It was therefore with special interest that 

 I studied the northern extension of this belt. 

 The fact that the isohyetals actually curve 

 eastward, i.e., that the precipitation is less as 

 we go northward on a given meridian, led me 

 to suppose that the difficulties would not dimin- 

 ish. It is certain, however, that the decreased 

 evaporation, due to the reduced temperatures 

 of the more northern parts of the dry belt, 

 much more than compensate for the difference 

 of rainfall. It is, moreover, currently believed 

 by the inhabitants of these more northern dis- 

 tricts, that the atmosphere is constantly kept 

 somewhat moist by the influence of the Pacific 

 coast and the Upper Columbia region. A 

 short sojourn on the Upper Missouri and Yel- 

 lowstone Rivers convinced me of the accuracy 



of this view. The general movement of the 

 atmosphere is from west to east. The moun- 

 tains to the westward are not high, — at least, 

 except at isolated points, — and do not, there- 

 fore, suffice to condense all the moisture that 

 passes over them. Near the sources of these 

 streams, as at Bozeman, crops are raised with- 

 out irrigation, whenever they can withstand the 

 frosts, although the rainfall is there only six- 

 teen inches per annum ; and the same is true 

 for eastern Dakota, with no greater precipita- 

 tion. It is also a matter of record, that the 

 temperature on this latitude diminishes toward 

 the east, and that colder weather prevails in 

 Minnesota than in Dakota, and in Dakota than 

 in Montana. The people attribute this to the 

 occurrence of what they denominate ' Chinook 

 winds;' i.e., winds laden with moisture, and 

 moderated in temperature from the warmer 

 regions of the Pacific slope. 



Notwithstanding this, it must still be con- 

 fessed, that, for all the lower parts of this region 

 of country, — the proper valleys of these rivers, 

 — irrigation is essential to successful agri- 

 culture. All statements to the contrary are 

 inspired by interest, usually by the railroad in- 

 terest, which hopes thereby to increase travel. 

 A number of instances of this came to my 

 notice, one in particular, in which a resident 

 who had published such a statement in a rail- 

 road circular was found reaping a field of un- 

 filled oats, six inches high, to be stacked for 

 fodder. 



Is this country, then, inhabitable, i.e., capa- 

 ble of sustaining a population? No one will 

 deny that it now possesses advantages for 

 stock-raising ; but a country which is only fit 

 for flocks and herds can never have sufficient 

 population to give it importance in a state. A 

 mining region may attract enough inhabitants 

 to become somewhat influential, and will re- 

 main so as long as the mines continue to yield. 

 But the only permanent and reliable basis of 

 population is agriculture. It is not necessary, 

 however, that all the land be devoted to agri- 

 culture : in fact, it really needs that only a 

 small portion of the soil be actually under the 

 plough to support comfortably a region in which 

 other operations can be carried on in parts not 

 adapted to agriculture. If that portion of the 

 Upper Missouri and Yellowstone valleys which 

 lies between the river and the first general rise 

 or terrace, including the valleys of the numer- 

 ous coulees, or creeks, that flow into it as far 

 as the same level would extend, could be ade- 

 quately irrigated, this area would furnish an 

 agricultural basis, sufficient, with the great 

 stock-raising region that lies back of it, to 



