OCR Text |
Show 14 as the standard of reference for the future astronomical positions determined by the survey. There are submitted results from the reports upon the determinations of the astronomical co- ordinates of the following main or primary stations : 1. Carlin, Nev.; 2. Battle Mountain, Nev.; 3. Austin, Nev.; 4. Saint George, Utah; 5. Fort Whipple, Ariz.; 6. Fort Fred Steele, Wyo.; 7. Laramie, Wyo.; deduced from observations made during the years 1871 and 1872. CARLIN, NEVADA* Geographical position- longitude, 116° 7' 20.6", latitude, 40° 42' 26.67" The astronomical station is situated west- northwest from Carlin, Nev., 344 feet from the track of the Central Pacific Railroad, and 1,406 feet from the Humboldt River, which is due south, and 550 feet from the railroad- bridge over a small creek entering the Humboldt from the south. The town has nearly 2,000 inhabitants, and is mainly located from east to west along the railroad- track. Physical geography details.- The ground around the station is level to the east and west; at a distance of 2,000 feet south and north a gentle rise commences. At a distance of two or three miles some slight hills, not more than 500 to 800 feet above the station, are visible. The elevation of the monument above the level of the sea is determined approximately to be 5,000 feet Meteorological conditions.- No meteorological observations of a general or special kind were made during the time of observations. As far as can be seen from the diary of the observer, there was a great diurnal change of temperature, bjF which the rate of the chronometer was much affected. Description of observatory.- The observations were taken in a common wall- tent, 10 by 10 feet, with an opening for the meridian line. The telegraphic instruments were placed in the northeast corner. The wires of the Western Union Telegraph Company were used for exchange of signals. The observer had no assistance but, Carlin being the starting-point for all parties, Mr. Francis Rlett acted as recorder during the time he was present. Description of instruments.- The astronomical instrument was a combined transit, made by Wiirdemann, numbered 16. It was of 26 inches focal length and 1£ inches aperture, and mounted on four pieces of redwood scantling 4 by 4 inches, which were planted in the ground about 4 feet, and fastened together above by board cross- pieces. For telegraphing, a switch- board was used, a description of which will be found in the report on Colorado Springs, Col. The observations were taken by eye and ear, using the sideral chronometer Negus 1344; for the exchange of signals, mean solar chronometer Hutton No. 288 was always used. Points with which connections were made were with the United States Lake- Survey Observatory at Detroit, Mich., and the United States Naval Observatory at Washington, D. C.- Detroit receiving the signals sent from Carlin and Washington. Siguals were sent on May 19, 23, and 24, 1871. Carlin was occupied by E. P. Austin; the observations at Detroit were conducted by Mr. O. B. Wheeler, assistant, United States Lake- Survey; at Washington, by Prof. John R. Eastman, United States Naval Observatory. The computations relating to Carlin and also the arrangement of the report were made by Dr. F. Kampf. Instrumental values, & c.- The value of one division of the striding-level was 1,14"; the value of one division of the zenith- level was 2.70//; of one revolution of the micrometer screw, 80.86". The wires of the |