362 
DR. DALTON ON THE CONSTITUTION OF THE ATMOSPHERE. 
1831, July 4. — Helvellyn air brought down from the summit by me ; wind S.W., 
with rain and fog. 
1. July 21. — Mixed two ounce measures of this air with one of hydrogen, so as to 
make six separate and successive explosions ; the hydrogen had iVths of a grain 
measure per cent, of oxygen, and this is allowed for in the corrected results. These 
results on the average gave 20-57 oxygen per cent. ; the highest was 20-68, and the 
lowest was 20'43. 
The residues of the six explosions were collected, and found to have 5 per cent, of 
hydrogen and 1 in 120 of oxygen. 
2. Mixed equal volumes of this Helvellyn air and the same bottle of hydrogen used 
above, and tired the mixture in successive portions. The average of six experiments 
gave 20’8 per cent, of oxygen. No oxygen was found in the residue. 
By comparing the results of 1 and 2, it would seem that more oxygen is reduced 
from common air by tiring equal volumes of common air and hydrogen than by tiring 
one volume of common air with half a volume of hydrogen. 
August 23. — Mixed 100 measures of town air and 120 of new pure hydrogen; this 
fired gave 21*5 oxygen per cent.; there was no oxygen in the residue. This would 
seem to point out ^^q^th of oxygen in the hydrogen, yet nitrous gas scarcely mani- 
fested so much. 
1832, July 26. — Mr. Green, jun., and Mr. John Taylor of the Manchester gas 
works, ascended in a balloon from Manchester after 6 p.m., a tine, clear, calm evening, 
barometer being 30 inches, thermometer 65° ; the balloon took a south direction, and 
landed in Cheshire about fourteen miles off. Mr. Taylor took a bottle of air when 
at the highest elevation, when the barometer stood at 16'8 inches, thermometer 55°; 
whence the altitude must have been about 15,000 feet. 
Capacity of the bottle = 2406 grains of water. 
On opening it under water in temp. 64° there entered 884 grains of water. 
The air was soon after its reception on the 27th transferred into two small phials 
for examination. 
The first phial was mixed with 60 per cent, of hydrogen, and fired in five portions ; 
it yielded 20’59 oxygen per cent. 
The second phial, mixed in like proportion, gave 20’65 oxygen per cent. 
Air from the town the next day, fired with the same phial of hydrogen as the pre- 
ceding, gave 20-95 on the average of five experiments. 
Air from Switzerland, & c. 
In the autumn of 1835 I was favoured with three samples of air taken in elevated 
situations in Switzerland by my friend W. D. Crewdson, jun. Esq., of Kendal. Each 
of these was taken in a two ounce phial by pouring out the contained water and 
