le,
it would be necessary to operate upon a large quantity of the two gasses
in a very troublesome and complicated apparatus. By this consideration,
Mr de la Place and I have hitherto been prevented from making the
attempt. In the mean time, the place of such an experiment may be
supplied by calculations, the results of which cannot be very far from
truth.

Mr de la Place and I deflagrated a convenient quantity of nitre and
charcoal in an ice apparatus, and found that twelve pounds of ice were
melted by the deflagration of one pound of nitre. We shall see, in the
sequel, that one pound of nitre is composed, as under, of

Potash 7 oz. 6 gros 51.84 grs. = 4515.84 grs.
Dry acid 8 1 21.16 = 4700.16.

The above quantity of dry acid is composed of

Oxygen 6 oz. 3 gros 66.34 grs. = 3738.34 grs.
Azote 1 5 25.82 = 961.82.

By this we find that, during the above deflagration, 2 gros 1-1/3
gr. of charcoal have suffered combustion, alongst with 3738.34 grs.
or 6 oz. 3 gros 66.34 grs. of oxygen. Hence, since 12 libs. of
ice were melted during the combustion, it follows, that one pound of
oxygen burnt in the same manner would have melted 29.58320 libs. of
ice. To which the quantity of caloric, retained by a pound of oxygen
after combining with charcoal to form carbonic acid gas, being added,
which was already ascertained to be capable of melting 29.13844 libs.
of ice, we have for the total quantity of caloric remaining in a pound
of oxygen, when combined with nitrous gas in the nitric acid 58.72164;
which is the number of pounds of ice the caloric remaining in the oxygen
in that state is capable of melting.

We have before seen that, in the state of oxygen gas, it contained at
least 66.66667; wherefore it follows that, in combining with azote to
form nitric acid, it only loses 7.94502. Farther experiments upon this
subject are necessary to ascertain how far the results of this
calculation may agree with direct fact. This enormous quantity of
caloric retained by oxygen in its combination into nitric acid, explains
the cause of the great disengagement of caloric during the
deflagrations of nitre; or, more strictly speaking, upon all occasions
of the decomposition of nitric acid.

_Of the Combustion of Wax._

Having examined several cases of simple combustion, I mean now to give a
few examples of a more complex nature. One pound of wax-taper being
allowed to burn slowly in an i