"At Fort Riley about sixty-nine per cent, of the annual precipitation 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 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 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, hypothetically, 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 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. "The vegetation of the plains along wagon tracks and rail road embankments shows a capability of production scarcely suggested by the surface where undisturbed: wherever the earth is broken up, the wild sunflower (_Helianthus_), and others of the taller-growing plants, though previously unknown in the vicinity, at once spring up.