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Show 784 the survey was made. During the progress of the survey frequent elevations are made of the water surface, and in connection with the drawing of the plan of the map they make a profile, which is a vertical section of the river, based on elevations established at the time the survey was made. From the pro-file he is able to determine what sections of the river con-tain rapids. He stated that rapids are in various slopes; one may have a fall of five feet in one hundred yards, or a swifter one a fall of ten feet in one hundred yards. R. 1871. As a rule, when water has a gradient of ten feet to the mile, there would be a lot of rapids in that mile. He stated that the topographers took elevations above and below each rapid, and that is done with an instrument. R. 1872. " BY THE SPECIAL MASTER: [ Referring to Exhibit No. 10, Page 55, Sheet T]. " Q. Just for the purpose of the record, just to illus-trate, take on this same sheet you refer to, from mile 204 to mile 206, what is the drop there? " A. From mile 204 to 206 it is the difference between 3765 and 3792; that would be about 27 feet in those two miles. " Q. How do you get that? " A. This is elevation ( indicating): here ( indicating), this 3760, or 3765, is practically the surface of the stream; at mile 204 it continues to rise to 3770 at that point, 3775, 3780, 3785, 3790 at No. 205; then it goes up to 3795 about there, and 3797 at that point. |