On Jolly’s Hypothesis as to the Cause of the Variations, etc. 429 
Art. LV.—On Jolly’s Hypothesis as to the Cause of the V. —— 
wn the Proportion of Oxygen in the Atmosphere; by Enw 
W. Moruey, M.D., Ph.D., Hurlbut Professor of Chatnis: 
try in Western Reserve College 
JOLLY has suggested a certain hypothesis as to the cause of 
those variations in the ratio of oxygen to nitrogen which are 
from time to time observed in tue atmosphere of a given place. 
He supposes that the volumes of air which exhibit the defi- 
ciency of oxygen are brought by currents from the tropical 
regions, that the deficiency of oxygen was caused in those 
regions, that it was caused by the consumption of oxygen in 
the oxidation of organic matter, and that at some places within 
the tropics this consumption is therefore considerably greater 
than the liberation of oxygen in the processes of vegetation. 
have proposed a second hypothesis. I mk that the 
volumes of air deficient in oxygen are brought by currents 
from an A api above the surface of the — that the de- 
ficiency of oxygen was caused while these volumes were at 
this pee at greet that it was caused by that assumed piven 
action according to which, in a high vertical column of a mix- 
ture of two gases, mens heavier will tend to become less abund- 
ant at the top of the ¢ ; 
The labor of osanbiiahin either hypothesis by experiment 
will probably be considerable. ropose to mention some 
0-01 or more; Z in the e second place, we must assert that the 
analyses which show a Mates of oxygen at latitude fifty 
degrees amounting to 0004 or 0-005 are grossly in error, and 
that the actual deficiencies are ee much less; or, in the third 
place, we must abandon the bepathesin: If the ‘analyses are 
