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UNITED STATES ENGINEER OFFICE,
AND SURVEYS WEST OF THE 100TH MERIDIAN,
CHEYENNE, WYOMING TERRITORY.
(1.) GEOGRAPHICAL POSITION OF STATION.
The station at Cheyenne, the latitude of which is N. 41° 7′ 46′′.62, and its longitude 28m 19.44 east of the Mormon observatory at Salt Lake, is situated in the western part of the town, in lot 11, block 413, and is northwest from the junction of the branchroad leading to the depot of Fort D. A. Russell with the main stem of the Union Pacific Railroad.
The town of Cheyenne, on the north side of the railroad, is the capital of Wyoming Territory; and besides the Union Pacific Railroad with its branch to Fort Russell, has a railroad-connection with Denver, Colorado. These facilities make it a flourishing place, and it possesses already, in addition to its public buildings, quite a number of substantial business-houses and attractive private residences.
A fine hotel, engine-houses, workshops, and other similar improvements, are among the sources of prosperity which spring directly from the railroad-company. Besides the traffic with Fort Russell, it is the depot for Red Cloud's agency, Fort Laramie, and the settlements on the North Platte.
The surrounding region affords unlimited pasturage, and cattle are said not only to subsist but grow fat on it during the whole year.
Agriculturally there is but little promise outside of what may be accomplished by
(2.) PHYSICAL-GEOGRAPHY DETAILS.
The site of Cheyenne is nearly or quite level; northward, however, there is a gradual swell of the land, and within a few miles it cuts off the extensive view one is accustomed to on the great plains. Eastward and southward there is the usual rolling and slightly-broken prairie; but in the southwest, Long's Peak, already white this September with snow, some seventy miles distant, looms up boldly above the horizon. West and northwest, low mountains, many of which mark the rim of the Laramie Plains, are just visible. Crow Creek, a moderate stream coming down from the foothills of this rim, forms a valley immediately west and south of the town, working its way apparently through mountain-drift, as the direct eruptive force of the Rocky Mountain system seems not to have reached so far east in this latitude.
(3.) METEOROLOGICAL CONDITIONS.
The determination of this station occupied the first three weeks in the month of October, 1872. There were no rains, nor any clouds, and, with the exception of two or three windy nights, the elements presented no obstacle whatever to a continued series of observations. In the early morning it would become cold enough to form
ice, making it sufficiently uncomfortable to restrain the ardor of an observer from extending his observations into the small hours of the night. From the experience of this season, and that of many others which I have undergone in former years in astronomical work, both on the plains and in the mountains, I am of the opinion that the best time of the year (so far as the weather is concerned) for astronomical observations in the Territories and the far Western States occurs in September and October. They are the months that fall between the rainy season of the summer and the stormy weather of the winter.
The following table shows the direction of the wind, and the estimated force, from 7 a. m. to 7 p. m. and from 7 p. m. to 7 a. m. The weather was clear all the time. Such an atmosphere, at an elevation of 6,000 feet, could not be otherwise than favorable for astronomical work.
General direction of wind.
Estimated force of wind.
7 a. m. to 7 p. m. 7 p. m. to 7 a. m. 7 a. m. to 7 p. m. 7 p. m. to 7 a. m.
A large wall-tent drawn over a framework formed the observatory. The opening for the meridian-line was furnished with a flap and curtains; the former served to protect the instrument from the weather when not in use, and the latter to keep off the wind and dust while observing. Here, and at other stations previously occupied, the opening for the meridian-line in the observatory was entirely unobstructed. Subsequently it was found to be an improvement to retain the ridge-pole (which commonly interferes but little with the completeness of the observations) as a support against the violent winds so prevalent in the country in which our operations are conducted. The tent was furnished with all the appliances of a field and temporary observatory, such as stools, stands, tables, and the like, and nothing was wanting as to equipment for firstclass field-work. The Western Union Telegraph Company furnished the line and other facilities for this station. Mr. Bates, one of the operators employed at the Cheyenne office, was assigned to do the telegraphing; and when business did not per
mit him to leave, which sometimes happened, Mr. Henderson, who was off duty at this hour, was obliging enough to supply his place gratuitously. Mr. F. R. Simonton was my assistant here, and kept, in conjunction with C. Herbert, an hourly meteorological record, besides his other duties as assistant.
(5.) DESCRIPTION OF INSTRUMENTS USED.
The transit used was the meridian-zenith-instrument No. 28, made by Würdemann, a description of which is given in Dr. Kampf's report, and it was mounted on a large block of wood. The instrumental values are, for one division of the micrometerscrew, o'.6216; of the striding-level A, 1".21; and of the zenith-level, 1".10.
The record of the observations for time, as well as the exchange of signals, with one exception (the night of the 14th), was made by means of the chronograph, of the form contrived by Professor Harkness, United States Naval Observatory. It consists of clock-work driven by a weight, and can be adjusted to run some two hours. The regulation of the movement is effected by a steel spring, with movable balances, striking on a fly-wheel. A cylinder is attached, covered with paper, and is made to revolve once a minute. Along this cylinder a screw carries a pen, which, being in the same circuit with the chronometer, records its breaks. The chronometric breaks are made every second, except the sixtieth, which is omitted, to mark the minute. Removing the paper from the cylinder, both the minutes and the seconds will be found, if the instrument is working properly, recorded in parallel lines, and the culminations of the stars observed, distinctly marked by arbitrary breaks, and easily read off.
The chronometer in use here was the Negus break-circuit No. 1499. It had a gaining-rate, +0.054, hourly average, at a mean temperature of 50°. The breakarrangement got out of order once, but it was readily repaired, and ran the rest of the season without giving any trouble.
A local circuit of sufficient force was produced by two cups of zinc and copper, a form known, I believe, among electricians as the Hill battery. It is simple, works a week or more without renewal, and the only possible objection to it for the purpose to which we apply it is that the sulphate is a little slow to act, particularly in cold weather.
The observatory was west of the telegraph-office, and the main connection was effected by a loop into one of the main overland wires and put in communication with Salt Lake by a switch at Ogden. The local connections, including the chronometer, the chronograph, and the observing-keys, were made by means of a switch-board, which also received the main circuit. The various wires being put in their proper
posts on this board, and the circuit closed, it required only the simple movement of sliding a switch-button to cut off or put on either circuit, and thus send the chronometric break, or receive that of the connected station on the chronographic sheet, as desired. The nights of the 1st, 3d, 8th, 9th, 10th, 11th, and 12th were occupied on latitude, in which time 257 results were obtained. The 5th, 14th, 16th, 18th, 19th, and 21st were successively put in on longitude. There were several other evenings when efforts were made in this direction, but failed from causes beyond my control. Mr. Austin did the observing at Salt Lake, while the observations at Cheyenne were made by myself, and also the longitude reductions for both stations. Prof. W. A. Rogers, of Harvard College Observatory, computed the latitude-observations, and they were subsequently revised, partially recomputed, and formulated by Dr. Kampf.
(7.) TABULATION OF STARS USED.
Tabulation of Stars used for Determination of Time at Cheyenne, Wyoming Territory, and Salt Lake City, Utah Territory.