OCR Text |
Show 78 this season was disbanded at Tucson, Ariz., and certain of its members ordered to Washington to prepare the necessary results. In 1872, fresh means having been appropriated by Congress, a more complete organization was had. The operations of this season were confined to a lesser area, principally in Utah, partially in Arizona and Southeastern Nevada. In 1873, the expedition was again sent into the field, and the character of the work was advanced measurably, in pursuance of the policy of perfecting the methods needed in a fully-developed geodetic survey of the entire western mountain region. During the season of 1873, in order to complete and connect the work extending from Nevada, Eastern California, and Northern Arizona to the east base of the Rocky Mountains, it was found essential to occupy points easily accessible by railroad- communication from the east. In 1874, connection between the eastern and western portions of the work was made more complete. The scheme of triangulation, based upon the positions of the several astronomical points determined along the east base of the Rocky Mountains, and the bases developed and measured therefrom, was extended to the west. In 1875, the survey for field-operations was organized in two divisions, designated respectively as the California and the Colorado sections. The Colorado section operated to extend the work in Colorado and New Mexico, begun in 1873 and further prosecuted in 1874, while the operations of the California section were laid in portions of the Southern Sierras and that branch of the coast range or ranges lying south of latitude 37°, and extending toward the Colorado desert southward of San Oorgonio Pass. One party was charged with an examination of the Colorado River, looking to a determination of the possibility of its diversion from its present channel for purposes of irrigation. The area occupied by the survey, and lying mostly south of the fortieth parallel, is as follows: Square milce. The part lying in Nevada 58,940 The part lying in California ,.- 40,625 The part lying in Arizona 60,120 The part lying in Utah i 44,015 The part lying in Colorado 37,550 The part lying in New Mexico 53,236 Points have been deterrainecTby astronomical means in Nebraska and Montana. The maps issued up to the present date represent an area of square miles as follows : Square miles. On a scale of 1 inch to 8 miles 192,217 On a scale of 1 inch to 4 miles 13,028 On a scale of 1 inch to 2 miles 1,091 CONCLUSION. In submitting the report for the year it is deemed proper to invite attention to the area covered by the survey in relation to the total area west of the one hundredth meridian, for which a detailed atlas is proposed as the final result. It may not be improper to speak of the position that the work has reached, as regards its methods, personnel, class of instruments, & c, resulting in an organization prepared for service in any portion of the entire territory west of the one hundredth meridian. Officers of the Corps of Engineers and line of the Army, being subject to changes of assignment whenever the exigencies of the service may require, cannot be considered as permanent assistants for a term of years: while most of the civilians whose |