13 



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. 

 (a.) Transit. 



The transit used was the meridian-zenith-instrument No. 28, made by Wiirde- 

 mann, 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 micrometer- 

 screw, o". 621 6; of the striding-level A, i".2i; and of the zenith-level, i".io. 



(I.} Chronograph. 



The record of the observations for time, as well as the exchange of signals, with 

 one exception (the night of the Hth), was made by means of the chronograph, of the 

 form contrived by Professor Harkness, United States Naval Observatory. It consists 

 of clock- woi'k 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, strik- 

 ing 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 instru- 

 ment is working properly, recorded in parallel lines, and the culminations of the stars 

 observed, distinctly marked by arbitrary breaks, and easily read off. 



(c.) Chronometer. 



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 break- 

 arrangement got out of order once, but it was readily repaired, and ran the rest of the 

 season without giving any trouble. 



(<i) Battery. 



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. 



(6.) CONNECTIONS. 



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 



