[ z 74 ] 
been produced from zinc was not altered, and filled 
the bottle as at flrft. 
Another inftance of this kind occurred to my ob- 
servation on the 19th of June 1772, when a quan- 
tity of air, half of which had been inflammable air 
from zinc, and half air in which mice had died, and 
which had been put together the 30th of July 
1771, appeared not to be in the leaft inflammable, 
but extinguifhed flame, as much as any kind of air 
•that I had ever tried. I think that, in all, I have 
had four inftances of inflammable air lofing its in- 
flammability, while it flood in water. 
Though air tainted with putrefaction extinguifhes 
flame, I have not found that animals or vegetables 
putrefying in inflammable air render it lefs inflam- 
mable. But one quantity of inflammable air, which 
I had fet by in May 1771, along with the others 
above mentioned, had had fome putrid flefh in it ; 
and this air had loft its inflammability, when it was 
examined at the fame time with the other in the De- 
cember following. The bottle in which this air 
had been kept, fmelled exa&ly like very ftrong 
Harrowgate water. I do not think that any perfon 
could have diftinguifhed them. 
I have made plants grow for feveral months in 
inflammable air made from zinc, and alfo from oak; 
but, though the plants grew pretty well, the air ftill 
continued inflammable. The former, indeed, was 
not fo highly inflammable as when it was frefh 
made, but the latter was quite as much fo ; and the 
diminution of inflammability in the former cafe, I at- 
tribute to fome other caufe than the growth of the 
plant, 
! - ' ; 
No 
