xcevi_ Proceedings of the Asiatic Soc. of Bengal. [N.S., XVI; 
think that it lies at a height of about 7 kilometres. 
13 
for some hundreds of kilometres, before beginning to fall to- 
wards the unutterable coldness of outermost s ace. 
14. Jn the lower region, with its falling temperature, a 
region which has been called the troposphere in distinction from 
the stratosphere above it. the gases of the atmosphere are kept 
level to mountain peak, show when analysed a_ practically 
constant constitution except in regard to water vapour 
15. 
g g for 
gases which form permanent constituents of the atmosphere, 
we must rule out ammonia, for it is brought down by the 
