508 - SEVENTH REPORT—1837. 
calculated as having been present in the jar at the commence- 
ment of the experiment, of which about 43 pints were discharged 
through the membrane in the course of the five days during 
which the observations were continued. 
The transmission took place more rapidly during the day 
because of the exposure of the jar to the sun and wind, which 
by the expansion caused within the vessel, and by the more 
rapid succession of aerial currents brought into contact with the 
external surface of the membrane, doubtless caused in a greater 
degree the transmission of the redundant oxygen. ‘The average 
quantity that escaped per diem did not much exceed 11 per 
cent., or did not quite amount to one pint in the 24 hours, but 
of course the transmission was more rapid at first, and dimi- 
nished gradually in quantity as the evaporation of the air within 
the jar approached more nearly to that of the atmosphere sur- 
rounding it. 
Believe me, dear Sir, yours faithfully, 
Cuas. DAUBENY, 
Professor of Chemistry and Botany, Oxford. 
END OF THE REPORTS. 
