Report Upon the Determination of the Astronomical Co-ordinates of the Primary Stations at Cheyenne, Wyoming Territory, and Colorado Springs, Colorado Territory, Made During the Years 1872 and 1873: Geographical and Geological Explorations and Surveys West of the One Hundredth Meridian, First Lieut. George M. Wheeler, Corps of Engineers, in Charge. Dr. F. Kampf and J. H. Clark, Civilian Astronomical Assistants