"On the Union Pacific road the profile also shows that for 900 continuous miles, from Sidney westward, the road has an average height of over 5,000 feet, and the lowest spot on that distance is more than 4,000 feet above the sea, whereas on the Northern route only about sixty miles at most are as high as 4,000 feet, and the corresponding distance of 900 miles, extending from the mouth of the Yellowstone to the valley of Clark's River, is, on an average, about 3,000 feet lower than the Union Pacific line. Allowing that 1,000 feet of elevation causes a decrease of temperature of three degrees, this would be a difference of nine degrees. There is, therefore, a substantial reason for the circumstance, now well authenticated, that the snows on the Northern route are much less troublesome than they are on the Union Pacific and Central Pacific routes" (Report, p. 43). That the Northern Pacific can be economically worked is demonstrated by a comparison of its grades with those of the line already constructed. The comparison is thus presented by Mr. Roberts:-- "The grades on the route across through the State of Minnesota and Territory of Dakota to the Missouri River will not be materially dissimilar to those on the other finished railroads south of it, passing from Chicago to Sioux City, Council Bluffs, etc.; namely, undulating within the general limit of about forty feet per mile, although it may be deemed advisable, at a few points for short distances, to run to a maximum of one foot per hundred or fifty-three feet per mile. There is sufficient knowledge of this portion of the route to warrant this assumption. And beyond the Missouri, along the valley of the Yellowstone, to near the Bozeman Pass, there is no known reason for assuming any higher limits. In passing Bozeman Summit of the Belt Range, and in going up the eastern side of the Rocky Mountains, it may be found advisable to adopt a somewhat higher gradient for a few miles in overcoming those summits. This, however, can only be finally determined after careful surveys. "The highest ground encountered between Lake Superior and the Missouri River, at the mouth of the Yellowstone, is only 2,300 feet above the sea; the low summit of the Rocky Mountains is but little over 5,000 feet, and the Bozeman Pass, through the Belt Range, is assumed to be about 500 feet lower. The height of the country upon which the line is traced, and upon which my estimate of cost is based, may be approximately stated thus, beginning at Lake Superior, going westward:-- Miles. Average height above the sea. To Dakota Valley, 300 1,200 feet. Yellowstone River, 300 2,200 " Along Yellowstone, 400 2,500 " Flathead Valley, 300 3,500 " Lewis or Snake River, 200 3,000 " Puget Sound, 500 400 " ----- 2,000