33 



report. Our barometers were always used in the same way 

 as in Colorado, the same rules being followed in every case. 

 We have reserved this matter, however, for the following 

 section, where we intend to discuss the methods we made use 

 of. It will be needless to repeat here the list of heights 

 already given in the topographical report. The only pecu- 

 liarity of our work in Utah was that the lower barometer 

 was situated for most of the time in the centre of the valley 

 of the East Branch of Smith's Fork. 



Our usual method of procedure was, on reaching the top 

 of the mountains, to lay the instruments on the ground and 

 build a monument, which not only served as a point of refer- 

 ence for our transit, but as a support for the barometer. 

 Then setting up the transit, and hanging the barometer by 

 the side of the monument, we first made the transit observa- 

 tions, and then those of the barometer; thus, giving the 

 barometer ample time to cool off and adjust itself, observa- 

 tions were then made on it, which lasted from half to three 

 quarters of an hour. The mean of these was taken in the 

 general calculations, but when greater care seemed to be 

 needed, each observation was calculated separately. 



We resorted to every expedient within our reach to make 

 our work correct. We remeasured the peaks of whose meas- 

 urements we were in any degree doubtful. When ascend- 

 ing one slope, if by means of our pocket-level we found we 

 were on a level with a summit on the other, we measured the 

 point on which we stood, and drew a sketch from it, which 

 gave us a good contour line to follow. 



Sketches were also made from the various peaks, which gave 

 us the drainage of the valley, and of its neighboring ones, 

 Black's and Henry's Forks. Our transit measurements 

 were generally checked by the pocket-sextant, in what is 

 known as a " tour d'horizon." We also made many measure- 

 ments of the dip of the strata, where any importance was 

 attached to them. 



In addition to the instruments carried in Colorado, we had 

 our transit with its tripod, and this made quite a load. 



