wilson.] PEIMAET TRIANGULATION" OF 1878. 655 



at this point by the boundary survey of Wyoming ; also made a sta- 

 tion on Medicine Butte, thus connecting with, my former work under 

 Clarence King in 1871 and '72. 



From Evanston we marched eastward by way of Fort Bridger and 

 Green Elver City to Eilot Butte, another one of my old points. Here I 

 spent two days, owing to the smoky condition of the weather, in obtain- 

 ing the necessary sights. 



We next visited Black Butte, also one of my former stations ; thence 

 returning to Eawlins. I revisited Separation Peak to obtain sights to 

 Wind Elver and Atlantic Peaks, not being able to see these points on my 

 first trip, as they were covered by clouds. Eemaining on the point all 

 night, I succeeded after sunset and before sunrise in obtaining the re- 

 quired observations. 



After taking another set . of azimuth observations from camp under 

 Eawlins Peak, I started my party for Cheyenne, there to be disbanded 

 for the season. Taking my theodolite, I took the train for Ogden, where 

 I connected the triangulation through Ogden and Willard Peaks with 

 the observatory established there by the Geographical Survey West of 

 the One Hundredth Meridian, under Lieut. G. M. Wheeler. I also con- 

 nected the work through the triaugulation of the Geological Exploration 

 of the Fortieth Parallel with the astronomical station made at Salt Lake 

 City by the -Coast Survey. 



REPORT ON THE PREtfARY TRTANOULATION OF 1878. 



Headquarters of the survey was at Cheyenne, as it had been the 

 previous season. The parties were fitted out as before, and shipped to 

 their respective points of departure. Mr. Jackson's party was shipped 

 with mine to Point of Eocks station, on Bitter Creek, where we arrived 

 on the morning of July 26. The day was spent in putting our luggage 

 and supplies in shape for transportation on the mules. 



The following morning, after the usual amount of trouble to get under 

 way, we started northward toward the Wind Eiver Mountains, continuing 

 our course without interruption until we reached the eastern branch of the 

 Little Sandy on the forenoon of July 29 ; here we halted to observe the 

 total eclipse of the sun, and we were very fortunate in having a splen- 

 didly clear day. The only observation we took was on the time of to- 

 tality. I observed with the telescope of my transit, Mr. Holmes with 

 the smaller glass of the gradienter, and Mr. Eccles with a smoked glass. 

 I made the time of totality 2 minutes 27 J seconds; Mr. Holmes, 2 min- 

 utes 27 seconds ; while Mr. Eccles made it 2 minutes and 26 seconds. 



It is not my intention to attempt here any description of the scene, 

 but will simply say that it was very interesting, and the effect quite 

 curious on ail who observed it. 



The next day we reached the foot of the Wind Eiver Mountains, 

 where we left the greater portion of the party to await our return. We 

 started on the morning of July 31, following up the west branch of the 

 Sweetwater, as we did the previous season, but finding that the snow 

 had all disappeared from the pass, we crossed the pass and followed up 

 a branch of the Big Popo Agie, and camped by a small lake near the 

 southeastern foot of the peak. 



On the morning of August 1 we took an early start, and being able 

 to ride to within a thousand feet of the summit, tying our animals to 

 some large rocks and shouldering our instruments, we soon reached the 

 toj) of Wind Eiver Peak. Looking down toward the northeast, we saw 

 plainly before us a very fine specimen of a living glacier; this I had 

 suspected the previous season, but at that time could not determine the 



