OCR Text |
Show 5 As near as multiplicity of duties will permit, the prosecuted and proposed labors in the different departments of the survey will be given, and the present condition of the results. ASTRONOMICAL. At the close of the fiscal year ending June 30,1872, the astronomical . parties were about taking the field: one of them occupying the Mormon observatory, Temple Square, Salt Lake City, during the entire season; while a series of observations for longitude and latitude, by the other two parties, were carried out at- 1st, Beaver, Utah; 2d, Pioche, Nev.; 3d, Gunnison, Utah; 4th, Cheyenne; 5th, Laramie; and € th, Fort Steele, Wyo. Ter. A station at the Union Pacific Railroad crossing of Green River, Wyoming Territory, was also occupied, but not completed. The requirements regarding the number and character of observations to be taken at each station were very rigid, and computed results show the probable errors to come within the accuracy expected of first class observations taken with the best field- astronomical instruments, which class of instruments, entirely new, were used at the points along the astronomical base that follows the liue of the Union Pacific Railroad. In addition to the observations at the main stations, sextant observations were conducted by the executive officers of the parties, having in view a latitude check upon topographical positions, and where the proximity of the telegraph- lines, and other circumstances, seemed to justify, longitude checks were also obtained by the comparison of the local times of the Salt Lake observatory, and the station selected by means of telegraphic signals. These field astronomical observations were mostly computed during the winter months by Lieutenant Marshall, assisted by Lieutenant Hoxie, while his services, away from other branches, were available. The main field astronomical parties for 1872 consisted of one principal assistant, one sub- assistant, and one general assistant, comprising, among their duties, the making of a series of hourly meteorological L observations that have aggregated severe labors. This plan has been I modified for the present season by the detail of first- class privates, two f in number, to each astronomical party, from the Battalion of Engineers, \ whereby each party numbers four individuals, and the elaborate system of astronomical and meteorological observations may be fully carried out. At this date the astronomical observations at the main stations for 1871 have been entirely reduced, with the exception of those at Pres-cott, Ariz. Ter. The data from the preliminary reductions have long since been used for mapping purposes. There remain unfinished, in the reductions for 1872- stations, certain parts of the latitude work, and a portion of the time reductions at the connecting or observatory station. In the hands of a skillful computer they are being rapidly completed. The services of Lieut. D. W. Lock wood, Corps of Engineers, spared from the United States lake survey for a period of two weeks, were made available for the reduction of sextant astronomical observations incomplete from the 1871 expedition. A careful, systematic programme has been prepared for placing all the reductions and incident data at main stations in a comprehensive form for report, that shall embrace a thorough and exhaustive history of the commencement, continuation, and completion of the observations aud their reduction, including the proper tabulation of the computations. Volume II, of the series proposed, will contain the summation of this material. |