ANNOTATIONS AND ADDITIONS. 41 



from the level of the sea, measurements of inaccessible 

 heights must generally be partly trigonometrical, and partly 

 barometrical. Estimations of the fall of rivers, of their 

 rapidity and of the length of their course, are so deceptive, 

 that the plain at the foot of the Rocky Mountains, nearest to 

 the summits above spoken of, was estimated, previous to the 

 important expedition of Capt. Fremont, sometimes at 8000, 

 and sometimes at 3000 feet. (Long's Expedition, vol. ii. 

 pp. 36, 362, 382, App. p. xxxvii.) It was from a similar 

 deficiency of barometrical measurements that the true eleva- 

 tion of the Himalaya continued so long uncertain : but now 

 the resources which belong to the cultivation of science 

 have increased in India to such a degree, that Captain 

 Gerard, when on the Tarhigarig, near the Sutlej, north of 

 Shipke, at an elevation of 19411 English feet, after breaking 

 three barometers, had still four equally correct ones remain- 

 ing. (Critical Researches on Philology and Geography, 

 1824, p. 144.) 



Fremont, in the expedition which he made in the years 

 1842 1844 by order of the Government of the United 

 States, found the highest summit of the whole chain of the 

 Rocky Mountains to the north north-west of Spanish, James's, 

 Long's, and Laramie Peaks. This snowy summit, of which 

 he measured the elevation barometrically, belongs to the 

 group of the Wind River mountains. It bears on the large 

 map, edited by Colonel Abert, Chief of the Topographical 

 Office at Washington, the name of Fremont's Peak, and is 

 situated in 43 10' lat. and 110 13' W. long, from 

 Greenwich, almost 5|- north of Spanish Peak. Its height, 



