262 



OBSERVATIONS ON THE 



never ascertained. — In these last situations the weather was very cold 

 and unsettled, the thermometer varying from 12° to 44°, with occasional 

 sprinklings of snow. Under analogous conditions the dryness of the air 

 increases with the elevation. I regret having overlooked the wet bulb 

 thermometer which from its principle and simplicity is, without a doubt, 

 the most correct measure of atmospherical humidity : a compensation may 

 however be suggested for the effect of the wind in accelerating absorption. 



t 



The face of the country, as far as it has been seen, affords a desolate 

 view to the botanist, but the field is not so unproductive as it looks, and 

 vegetation though scanty, will be found to exhibit many new species and 

 peculiarities. A generic character prevails : most of the plants being 

 armed with spiculse: furze and spartium form the general clothing of 

 the soil. In animal nature, the scene is equally fertile in variety: and in 

 geology, there is much to interest inquiry; and if elevation is an object 

 of science, the mountain ranges here offer facilities of ascent, which the 

 steepness of the southward Himalaya, the snow and the cloudy climate, 

 entirely oppose. It is obvious that angles taken from an altitude of 

 twenty-one thousand feet, would be subject to little or no refraction where 

 the visual ray passes through so thin a medium. From such a position, the 

 highest levels of the country would be accurately indicated, assuming the 

 base to be correct, which barometrical observations would sufficiently 

 establish. Objects visible upon the plane of the horizon, at a distance of one 

 geographical degree, would be actually elevated three thousand feet : the 

 extreme height of the mountain range would thus be readily determined, 

 as the observations would be liable to little discrepancy from atmospheric 

 causes. The climate in summer is sufficiently favorable for a stationary 

 residence, and at twenty thousand feet, one would rarely be exposed to a 

 severer night temperature than 20°, or during the day, to one of ten 

 below 45°, very commonly much higher, from the power of the sun's rays. 

 Observations might be made on the diminished pressure of the air upon 



