CHAPTER- II. 



ELEVATIONS. 



Elevations have been measured by cistern barometer, aneroids, and 

 the vertical circle of the gradienter. I\Iost of the mountain-summits 

 in the western part of the Elk sj'^stem and on the great plateau were 

 measured trigonometrically by the vertical circle of the gradienter, 

 based on the barometric elevations in the eastern jjart of the system. 



KETISION OF THE HEICIHTS OF SUMMITS IN THE SAWATCH AND ELK 



SYSTEMS. 



For a more accurate determination of the elevations of these mount- 

 ains, I have employed a combination of the barometrical and trig- 

 onometric methods. By means of the vertical angles, between the peaks, 

 their relative elevation has been determined with considerable accuracy. 

 Then the heights of the several peaks, as measured by barometer, are 

 reduced .to a common point by use of these relative elevations. The 

 mean of these results, giving suitable weights, gives a mean elevation 

 for this common point, and, applying to it the difference in elevation, 

 gives the heights of the other peaks. The accuracy of the results depends 

 on the character of the leveling, the number of barometric elevations, 

 and situation of the barometric base to which they are referred. In the 

 Sawatch range, within the area over which I worked during the season 

 of 1873, four peaks were measured by cistern-barometer. The barometric 

 observations on these peaks were referred for a base to those taken near 

 the summit of Mount Lincoln, at an elevation of 14,194 feet. The dif- 

 ference of elevation in no case exceeds 400 feet, and the greatest distance 

 (to Mount Princeton) is forty-two miles, while the least (to La Plata 

 Mountain) is but twenty-nine miles. 



In the Elk Mountains tive peaks have been measured by cistern -barom- 

 eter, and referred to Mount Lincoln as a base. Of these the nearest 

 to Mount Lincoln is Italian Peak, forty-four miles from it, while the one 

 farthest off is Crested Butte, which is at a distance of fifty-five miles. 

 The greatest difference in elevation is more than 2,000 feet. 



The following is a summary of the work of reduction of the barometric 

 elevations in these two mountain-systems, with the resulting elevations: 



Sawatch ranfje. 



Relative ele- 

 vation. 



Elevation of 

 baiometer. 



Elevation of 

 La Plata 

 Mountain. 



Mean eU'va- 

 tion. 



La Plata Monntain 



Grizzly Peak 



ilonnt nar\-ard . . . 

 Mount Princeton . . 



Feet. 





 — 355 



— 115 



Feet. 

 14, 302 



13, 9C-2 



14, 384 

 14, 190 



Feet. 

 14,302 

 14,317 

 14, 320 

 14, 314 



Feet. 

 14,311 



13, 950 



14, 375 

 14, 196 



4-.>9 



