242 On the Height of the 



good as to communicate to me the particulars of them : I subjoin 

 his letter. 



The height of Dhawalagiri and four contiguous mountains 

 has been computed from the data furnished by Captain Blake's 

 survey; using the formula which I gave in the I2th volume of 

 Asiatic Researches; and taking terrestrial refraction at one 

 eleventh of the contained arc, which is the estimated mean 

 quantity of ordinary refraction. The elements of the compu- 

 tation are exhibited in a tabular form accompanying. 



The elevation of Dhawalagiri, taking the mean of three sets 

 of observations, is thus found to be 27,615 feet above the plains 

 of Gorakhpur, or 28,015 above the sea; differing only 64 feet 

 from the computation founded on Captain Webb's survey. 



Or allowing for terrestrial refraction one twelfth of the base ; 

 which was the rate that appeared to bring the result of the 

 different observations taken by Captain Webb, nearest to agree- 

 ment ; the elevation of Dhawalagiri, deducible from the later 

 survey, is 27,704 feet above Gorakhpur, or 28,104 above the sea; 

 differing from that deduced from the former survey by no more 

 than 27 feet. 



This near coincidence authorizes an expectation, that the 

 true height of Dhawalagiri, when it shall be accurately deter- 

 mined, will be found very little wide of 28,000 feet. 



Captain Blake's survey determines likewise the positions 

 and altitudes of four other conspicuous mountains in the vi- 

 cinity of Dhawalagiri. 



About thirty-six miles east of it, and equally distant from 

 the plain, is a mountain which rises to the height of 23,708 feet 

 above Gorahhpur, or 24,108 feet above the sea. 



Nearly midway between them, but somewhat less remote, is 

 situated a mountain called Set-ghar* or Nepal; its position, as 

 the last mentioned name implies, is near to Nepal proper. 

 The elevation of the summit is 24,861 feet above the level of 

 Gorakhpur, or 25,261 feet above that of the sea. 



Twenty miles west of Dhatvalagiri, but less remote from the 



* Probably Swetagliar, or the White Tower. 



