HIMALAYA MOUNTAINS. a 266 



The following table exhibits a comparifon of this refult, with other 

 computations made on different rates of refraction. 



Distance Inierc. AH. Height, allowing for refraction, 



Station. arc by 



hs miles. in deg. obs. | | | rr rr tV tV 



A ..„. 89^ 10 17' 5!* 5048' 21875 26663 27110 27176 27558 27626 27855 



C 109-j^ l n 29' 36".6 2° 19' 24348 26716 27308 27792 27900 27991 28294 



D 136^ 1° 58';4S'f' / 1" 22' 21338 25494 25554 27384 27573 27773 28286 



' Mem 23520 26091 26784 27551 27677 27797 28145 

 ■EVWeWe difference 3537 1222 774 408 342 365 439 



It is apparent from infpeclion, that the obfervations at the fiations 

 A and D agree bed, and if that computation be neareft the truth, 

 wherein the extreme differences are leafr^ the conclusion will be, that 

 the height is about 27550 feet; fuch being the elevation deduced from 

 the mean of obfervations calculated- according to middle refraction. 



The limit of error ariilng from refraclion muff be taken at lefs than 

 850 feet, as the obfervations at A and C coincide for the height of 

 26600 feet, f th of the contained arc being allowed for refraclion ; 

 and thofe at C and D, for an elevation of 28290 feet, T y h being allow- 

 ed; while thofe at A and D do fo for the mean altitude of 27565 feet, 

 refraction being taken at the middle rate of T V h ; and a larger allow- 

 ance then £ tb of the intercepted arc, which would exceed mean celeftial 

 refraclion for like altitudes, cannot be requifite, without very wide 

 difagreement in obfervations made on different days, which would 

 mark extraordinary refraclion ; but that is not the cafe with thofe in 

 queflion. 



The limits of error in refpecl of the obfervations themfelvc?, whe- 

 ther for the diflance, or for the altitude, are more confined, fince the 



