n 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 least
inflammable, but extinguished flame, as much as any kind of air that I
had ever tried. I think that, in all, I have had four instances of
inflammable air losing its inflammability, while it stood in water.

Though air tainted with putrefaction extinguishes flame, I have not
found that animals or vegetables putrefying in inflammable air render it
less inflammable. But one quantity of inflammable air, which I had set
by in May 1771, along with the others above mentioned, had had some
putrid flesh in it; and this air had lost its inflammability, when it
was examined at the same time with the other in the December following.
The bottle in which this air had been kept, smelled exactly like very
strong Harrogate water. I do not think that any person could have
distinguished them.

I have made plants grow for several months in inflammable air made from
zinc, and also from oak; but, though the plants grew pretty well, the
air still continued inflammable. The former, indeed, was not so highly
inflammable as when it was fresh made, but the latter was quite as much
so; and the diminution of inflammability in the former case, I attribute
to some other cause than the growth of the plant.

No kind of air, on which I have yet made the experiment, will conduct
electricity; but the colour of an electric spark is remarkably different
in some different kinds of air, which seems to shew that they are not
equally good non-conductors. In fixed air, the electric spark is
exceedingly white; but in inflammable air it is of a purple, or red
colour. Now, since the most vigorous sparks are always the whitest, and,
in other cases, when the spark is red, there is reason to think that the
electric matter passes with difficulty, and with less rapidity: it is
possible that the inflammable air may contain particles which conduct
electricity, though very imperfectly; and that the whiteness of the
spark in the fixed air, may be owing to its meeting with no conducting
particles at all. When an explosion was made in a quantity of
inflammable air, it was a little white in the center, but the edges of
it were still tinged with a beautiful purple. The degree of whiteness in
this case was probably owing to the electric matter rushing with more
violence in an explosion than in a common spark.

Inflammable ai