SPITI VALLEY, &c. 



201 



scarcely attainable by any length of time, while in Calcutta opium cannot 

 be dried for medical purposes without artificial heat. In Europe the 

 rhubarb roots, at the end of a year, generally require to be baked in an 

 oven before they can be pulverized. 



Hygroraetrical considerations seem to have been entirely neglected 

 by travellers in India. I was fortunate enough in being put in possession 

 of Kater's hygrometer, in the tour I made to the sources of the 

 Hi/phasis and Chmdb, and across the high land of Rupshu into Spilt, 

 which afforded me an opportunity of comparing the state of the air on 

 both sides of the Himalaya, and the degree of humidity that belonged to 

 different elevations and situations ; tlie general conclusions from which 

 were, that the atmosphere of the interior regions was more than twice 

 as dry as that which rested upon the southern hills ; — that the aspect 

 of vegetation and the rocks corresponded with the indications of the 

 hygrometer, and that the climate of the valley of Spil'i at an elevation 

 of between twelve and thirteen thousand feet, in October, was infinitely 

 more arid than that of Sahdlliu at four thousand feet, in May and 

 June, when the wind becomes heated and the country parched up. The 

 temperature in the former was between 40° and 45°; — in the latter 80°. 

 The minimum of die hygrometer, in a scale that indicated 1,200, as the 

 point of saturation was .0.38,* the barometer being then ID. 270, thermometer 

 53°. For a succession of days the range varied between .042* and .055* 

 for the least, and 170 to the greatest, which last always occurred 

 sometime after sunrise j". At elevations of nearly fifteen ihousand feet, 

 the results were not so decisive owing to lht> presence of clouds in the air 

 and lo the great difiereiu (> of leni[)(Maturc, the correction for w iiich 1 have 



* So wiittt n in the MS. ; perhaps intended for 38, 42 and 55. 



f At Siibiit/iii, Katku's liy^romotiT scklom fell under 100 in a temperature exceeding 90". — 

 In Spill, iu October, the di piesbioii was generally -l.) in an atiuosplicro of 60 degrees. 



r a 



