VOL. LXXIX.] PHILOSOPHICAL TRANSACTIONS. 549 



waters of the lake rise and fall very little, being supplied by a constant and un- 

 varying source, neither augmented by the influx of any current, nor diminished 

 by any stream running from it. The lake is at least '20 miles in circumference, 

 and standing in a very bleak situation is frozen for a great part of the year. The 

 people employed in collecting these salts are obliged to quit their labour so early 

 as October, on account of the ice. Tincal is used in Thibet for soldering and 

 to promote the fusion of gold and silver. Rock salt is universally used for all 

 domestic purposes in Thibet, Boutan, and Naphaul. 



The thermometer at Tissoolumboo during the month of October was, on an 

 average, at 8 o'clock in the morning 38°, at noon 46°, and d o'clock in the 

 evening 42°. The weather clear, cool, and pleasant, and the prevailing wind 

 from the southward. During the month of November we had frosts morning 

 and evening, a serene clear sky, not a cloud to be seen. The rays of the sun 

 passing through a medium so little obscured had great influence. The thermo- 

 meter was often below 30° in the morning, and seldom above 38° at noon in the 

 ^hade; wind from the southward. 



Of the diseases of this country, the first that attracts our notice, as we ap- 

 proach the foot of the hills, is a glandular swelling in the throat, which is known 

 to prevail in similar situations in some parts of Europe, and generally ascribed 

 to an impregnation of the water from snow. The disease being common at the 

 foot of the Alps, and confined to a tract of country near these mountains, has 

 first given rise to the idea of its being occasioned by snow water. If a general 

 view of the disease, and situations where it is common, had been the subject of 

 inquiry, or awakened the attention of any able practitioner, we should have 

 been long since undeceived in this respect. On the coast of Greenland, the 

 mountainous parts of Wales and Scotland, where melted snow must be conti- 

 nually passing into their rivers and streams, the disease is not known, though it 

 is common in Derbyshire, and some other parts of England. Rungpore is about 

 100 miles from the foot of the hills, and much farther from the snow, yet the 

 disease is as frequent there as in Boutan. In Thibet, where snow is never out 

 of view, and the principal source of all their rivers and streams, the disease is 

 not to be met with ; but what puts the matter past a doubt, is the frequency of 

 the disease on the coast of Sumatra, where snow is never to be found. On 

 finding the vegetable productions of Boutan the same as those of the Alps in 

 almost every instance, it occurred to me, that the disease might arise from an 

 impregnation of the water by these plants, or the soil probably possessing similar 

 qualities, the spontaneous productions of both countries, with very few excep- 

 tions, being so nearly alike. It however appears more probable, that the disease 

 is endemial, proceeding from a peculiarity in the air of situations in the vicinity 

 of mountains with such soil and vegetable productions. I am the more inclined 



