ectric spark, than I have before
observed it to have been by a mixture of iron filings and brimstone.
When the electric spark was taken in it, it was confined by a quantity
of water tinged blue with the juice of archil, but the colour remained
unchanged.

I put two _wasps_ into inflammable air, and let them remain there a
considerable time, one of them near an hour. They presently ceased to
move, and seemed to be quite dead for about half an hour after they were
taken into the open air; but then they came to life again, and presently
after seemed to be as well as ever they had been.

SECTION VI.

_Of FIXED AIR._

The additions I have made to my observations on _fixed air_ are neither
numerous nor considerable.

The most important of them is a confirmation of my conjecture, that
fixed air is capable of forming an union with phlogiston, and thereby
becoming a kind of air that is not miscible with water. I had produced
this effect before by means of iron filings and brimstone, fermenting in
this kind of air; but I have since had a much more decisive and elegant
proof of it by _electricity_. For after taking a small electric
explosion, for about an hour, in the space of an inch of fixed air,
confined in a glass tube one tenth of an inch in diameter, fig. 16, I
found that when water was admitted to it, only one fourth of the air was
imbibed. Probably the whole of it would have been rendered immiscible in
water, if the electrical operation had been continued a sufficient time.
This air continued several days in water, and was even agitated in water
without any farther diminution. It was not, however, common air, for it
was not diminished by nitrous air.

By means of iron filings and brimstone I have, since my former
experiments, procured a considerable quantity of this kind of air in a
method something different from that which I used before. For having
placed a pot of this mixture under a receiver, and exhausted it with a
pump of Mr. Smeaton's construction, I filled it with fixed air, and then
left it plunged under water; so that no common air could have access to
it. In this manner, and in about a week, there was, as near as I can
recollect, one sixth, or at least one eighth of the whole converted into
a permanent air, not imbibed by water.

From this experiment I expected that the same effect would have been
produced on fixed air by the fumes of _liver of sulphur_; but I was
disappointed in that expectatio