1921.| The Eighth Indian Sctence Congress. X¢Vil 
first shower of rain after its formation at the surface; and 
ozone, because its activity causes it a short life ; and further 
it is believed for several reasons that we must rule out hydro- 
n. The gases neon, krypton and xenon on account of their 
high molecu)-r weights, cannot be expected to occur in any 
quantity above the troposphere ; for the stratosphere is in 
250 
200 
\ Helium 
150 : 
iW aN 
Ye Nitrogen 
m Ra" 
20}| Oxy: Height at| which aigfusioan 
Argon- : ws wma to é 
0 20 40 60 go 480—- 100% 
Fig.2 
the level at which a sample could be obtained the greater 
would be the proportion of its lighter gases. For the extreme 
pper air we are left therefore, with argon, oxygen, nitrogen 
and helium, and the distribution of these has been calculated 
oe r * Y 2 
is represented by the conditions of Fig. 2 which is a reproduc- 
tion from a recent paper on the subject by Chapman and 
Milne. ! is 
16. Ifa horizontal line be ruled anywhere on this dia- 
gram, the composition of the atmosphere at the height crossed 
by the line will be given by the intersections of the various 
|< "The atmosphere at great heights”; Q. J. R. Met. Soc., Oct. 1920, 
Pp. 379. 
