298 KHASIA MOUNTAINS. Chap. XXX. 



and further tends to prove that the snowy mountains, 

 seen from the southward, are not on the axis of a moun- 

 tain chain, and do not even indicate its position ; but 

 that they are lofty meridional spurs which, projecting 

 southward, catch the moist vapours, become more deeply 

 snowed, and protect the dry loftier regions behind. 



The most conspicuous group of snows seen from the 

 Khasia bears N.N.E. from Myrung, and consists of three 

 beautiful mountains with wide-spreading snowy shoulders. 

 These are distant (reckoning from west to east) respectively 

 164, 170, and 172 miles from Myrung, and subtend angles 

 of + 0° 4' 0", — 0° V 30", and — 0° 2' 28".* From 

 Nunklow (940 feet lower than Myrung) they appear 

 higher, the western peak rising 14' 35" above the horizon ; 

 whilst from Moflong (32 miles further south, and eleva- 

 tion 6,062 feet) the same is sunk 2' below the horizon. 

 My computations make this western mountain upwards of 

 24,000 feet high ; but according to Col. Wilcox's angles, 

 taken from the Assam valley, it is only 21,600, the others 

 being respectively 20,720 and 21,475. Captain Thuillier 

 (the Deputy Surveyor General) agrees with me in consi- 

 dering that Colonel Wilcox's altitudes are probably much 



* These angles were taken both at sunrise and sunset, and with an excellent 

 theodolite, and were repeated after two considerable intervals. The telescopes 

 were reversed after each observation, and every precaution used to insure 

 accuracy ; nevertheless the mean of one set of observations of angular height 

 often varied 1' from that of another set. This is probably much due to atmo- 

 spheric refraction, whose effect and amount it is impossible to estimate accurate!}* 

 in such cases. Here the objects are not only viewed through 160 miles of 

 atmosphere, but through belts from between 6,000 to 20,000 feet of vertical 

 height, varying in humidity and transparency at different parts of the interval. If 

 we divide this column of atmosphere into sections parallel to those of latitude, 

 we have first a belt fifteen miles broad, hanging over the Khasia, 2,000 to 4,000 

 feet above the sea; beyond it, a second belt, seventy miles broad, hangs over the 

 Assam valley, which is hardly 300 feet above the level of the sea; and thirdly, 

 the northern part of the column, which reposes on 60 to 100 miles of the Bhotan 

 lower Himalaya : each of these belts has probably a different refractive 

 power. 



