tion, be the means by which the phlogiston, which is
conveyed into the system by nutriment, is converted into that form or
modification of it of which the electric fluid consists.

These two states of phlogiston may be conceived to resemble, in some
measure, the two states of fixed air, viz. elastic, or non-elastic; a
solid, or a fluid.

THE APPENDIX.

In this Appendix I shall present the reader with the communications of
several of my friends on the subject of the preceding work. Among them I
should with pleasure have inserted some curious experiments, made by Dr.
Hulme of Halifax, on the air extracted from Buxton water, and on the
impregnation of several fluids, with different kinds of air; but that he
informs me he proposes to make a separate publication on the subject.

NUMBER I.

_EXPERIMENTS made by Mr. Hey to prove that there is no OIL of
VITRIOL in water impregnated with FIXED AIR._

It having been suggested, that air arising from a fermenting mixture of
chalk and oil of vitriol might carry up with it a small portion of the
vitriolic acid, rendered volatile by the act of fermentation; I made the
following experiments, in order to discover whether the acidulous taste,
which water impregnated with such air affords, was owing to the presence
of any acid, or only to the fixed air it had absorbed.

EXPERIMENT I.

I mixed a tea-spoonful of syrup of violets with an ounce of distilled
water, saturated with fixed air procured from chalk by means of the
vitriolic acid; but neither upon the first mixture, nor after standing
24 hours, was the colour of the syrup at all changed, except by its
simple dilution.

EXPERIMENT II.

A portion of the same distilled water, unimpregnated with fixed air, was
mixed with the syrup in the same proportion: not the least difference in
colour could be perceived betwixt this and the above-mentioned mixture.

EXPERIMENT III.

One drop of oil of vitriol being mixed with a pint of the same distilled
water, an ounce of this water was mixed with a tea-spoonful of the
syrup. This mixture was very distinguishable in colour from the two
former, having a purplish cast, which the others wanted.

EXPERIMENT IV.

The distilled water impregnated with so small a quantity of vitriolic
acid, having a more agreeable taste than when alone, and yet manifesting
the presence of an acid by means of the syrup of violets; I subjected it
to some other tests of acidity. It formed