414 CLIMATE OF SIKKIM. Appendix F. 



or of respiration when the body was at rest, below 17,000 feet. At 

 that elevation, after resting a party of eight men for an hour, the 

 average of their and my pulses was above 100°, both before and after 

 eating ; in one case it was 120°, in none below 80°. 



Not only is the frame of a transient visitor unaffected (when at rest) 

 by the pressure being reduced from 30,000 to 13,000 pounds, but 

 the Tibetan, born and constantly residing at upwards of 14,000 feet, 

 differs in no respect that can be attributed to diminished pressure, 

 from the native of the level of the sea. The average duration of life, 

 and the amount of food and exercise is the same ; eighty years are 

 rarely reached by either. The Tibetan too, however inured to cold 

 and great elevations, still suffers when he crosses passes 18,000 or 

 19,000 feet high, and apparently neither more nor less than I did. 



Liebig remarks (in his " Animal Chemistry ") that in an equal 

 number of respirations,* we consume a larger amount of oxygen at 

 the level of the sea than on a mountain ; and it can be shown that 

 under ordinary circumstances at Dorjiling, 20*14 per cent, less 

 is inhaled than on the plains of India. Yet the chest cannot ex- 

 pand so as to inspire more at once, nor is the respiration appreciably 



* For the following note I am indebted to my friend, C. Muller, Esq., of 

 Patna : — 



According to Sir H. Davy, a man consumes 45,504 cubic inches of oxygen in 

 twenty-four hours, necessitating the inspiration of 147,520 cubic inches of 

 atmospheric air. — At pressure 23 inches, and temp. 60°, this volume of atmos- 

 pheric air (dry) would weigh 35,138*75 grains. — At pressure 30 in., temp. 80°, it 

 would weigh 43,997*63 gr. 



The amount of oxygen in atmospheric air is 23*32 per cent, by weight. The 

 oxygen, then, in 147,520 cubic inches of dry air, at pressure 23 in., temp. 60°, 

 weighs 8,194*35 gr. ; and at pressure 30 in., temp. 80°, it weighs 10,260*25 gr. 



Hence the absolute quantity of oxygen in a given volume of atmospheric air, 

 when the pressure is 23 in., and the temp. 60°, is 20*14 per cent, less than when 

 the pressure is 30 in. and the temp. 80°. 



When the air at pressure 23 in., temp. 60°, is saturated with moisture, the 

 proportion of dry air and aqueous vapour in 100 cubic inches is as follows : — 



Dry air . . . 97*173 

 Vapour . . .2*827 



At pressure 30 in., temp. 80°, the proportions are : — 



Dry air . . . 96*133 

 Vapour . . . 3*867 



The effect of aqueous vapour in the air on the amount of oxygen available for 

 consumption, is very trifling ; and it must not be forgotten that aqueous vapour 

 supplies oxygen to the system as well as atmospheric air. 



