454 GEOLOGICAL SURVEY OF THE TERRITORIES. 



inequality increases until we pass the BockyMour. tains. "Contrasting 

 the two stations, New York and Fort Laramie," says Professor Foster, 

 " it will be seen that on the seaboard about 48 per cent, of the yearly 

 precipitation occurs during the fall and winter, while on the Plains 

 only 25 per cent, occurs during that period, and that, while on the sea- 

 board the precipitation is nearly uniform during the four seasons, three- 

 fourths of the precipitation on the Plains occurs during spring and sum- 

 mer," The same excess in the rain-fall of spring and summer is, I think, 

 noted with comments in Blodgett. 



At Fort Eiley about 69 per cent, of the annual precipitation is in 

 spring and summer ; at Fort Kearney 81, and at Fort Laramie 72 per 

 cent. From observations at Forts Harker, Hays, and Wallace, on the 

 line of this road, the same rule seems to hold good. Becords have not 

 been long enough continued at these three posts to give a long average, 

 but the mean appears to be between 17 and 19 inches at Hays and Wal- 

 lace, and possibly rather more at Harker. The actual average for 1868 

 and 1869 at Hays is 18.76 inches, and for the first six months of 1870 the 

 record is 10.68 inches. At Wallace the record for 1869 was over 17 

 inches, and in 1870, up to October 1, about the same amount had fallen. 



Without records there can be only conjecture ; and 1 can only remark 

 that there does not seem to be much diminution in the annual rain-fall 

 until we get as far west as the one hundred and third meridian. Thence 

 to the base of the mountains, (except perhaps in the timbered portions 

 of the great divide, south of the line of this railway,) the annual average 

 may be possibly two or three inches less than in the midst of the Plains : 

 a peculiarity explained, hypothetically, by the fact that the region " lies 

 to the westward of the general course of the moister currents of air 

 flowing northward from the Gulf of Mexico, and is so near the mount- 

 ains as to lose much of the precipitation that localities in the Plains east 

 and northeast are favored with. The mountains seem to exercise an in- 

 fluence — electrical and magnetical? — in attracting moisture, which is 

 condensed in the cooler regions of their summits, while the plains at their 

 feet may be parched and heated to excess." This explanation may be 

 fanciful, but the fact remains that near the mountains the rains seem to 

 decrease north of the great divide ; fortunately, however, this occurs in 

 a region where irrigation may be applied extensively, and where there 

 is sufficient moisture to nourish bountiful crops of grass. 



A striking difference exists between the rain-fall in New Mexico and 

 that on the Plains. While the annual amount at Santa Fe and at Fort 

 Hays is nearly equal, the larger proportion of the rain-fall at Hays comes 

 in spring and summer, while at Santa Fe it is delayed till summer and 

 autumn. Hence the farmer at Hays may have his wheat crop matured 

 in early summer without irrigation, while the same crop in New Mexico 

 requires to be irrigated. The usual period for the nourishing rains to 

 begin, in New Mexico, is about the first of August, a time when they 

 are usually light on the Plains. 



Theory suggested that the cereals ought to sustain themselves with- 

 out irrigation at least as far west as the head streams of the Smoky 

 Hill Eiver; and the president and directors of the railway caused exper- 

 iments to be made. Wheat sown in April last matured in July, about 

 the one hundred and first meridian, yielding merchantable grain. 

 Maize formed ears, and oats headed well, but neither filled in a satis- 

 factory manner, owing to the fact that the dry and hot season comes 

 on when their grains are forming. Both can be raised as fodder to any 

 extent desired. All along the railway, throughout the season, stalks of 

 maize and oats could be seen growing, where seeds had been dropped by 



