480 buffalo' land. 



fertile* (he Mississippi Valley, including the broad, gra»v 

 plains, is derived from the Gulf of Mexico. 



" At Fort Riley about sixty-nine per cent, of the annual pre- 

 Oipifcation is in spring and summer; at Fort Kearney, eighty, 

 one; and at Fort Laramie, seventy-two per cent.' From 

 observations at Forts Harker, Hays, and Wallace, on the line 

 of this road, the same rule seems to hold good. Records have 

 not been long enough continued at these three posts to give a 

 long average, but the mean appears to be between seventeen 

 and nineteen inches at Hays and Wallace, and possibly rather 

 more at Harker. The actual average for 1868 and 1869 at 

 I lay- 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 seventeen inches, and in 1870, up to October 1, about the 

 same amount had fallen. 



"Without records there can be only conjecture; and I 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, hypothetical^ by 

 the fact that the region ' lies to the westward of the general 

 course of the moisture currents of air flowing northward from 

 the Gulf of Mexico, and is so near the mountains as to lose 

 much of the precipitation that localities in the plains east and 

 north-east are favored with. The mountains seem to exercise an 

 influence-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 ex- 



