1810.] 
taper to the mixture of these powerful 
materials. 
{ am aware, that I shall be told, there 
are analogies by which the theory of 
Dr. Jones may be upheld; but those 
which are most in point, it is but candid 
to anticipate. First then, with respect 
to the well-known experiment of the in- 
flammable air-pistol. In this, when hy- 
drogen gas and. atmospheric air are 
mixed, it was observed, that (the elecs. 
tiic spark being employed in Jieu of a 
mach or paper,) the interior of the bar- 
rel was always moist, but the cork press? 
ed into thé end of the barrel is uniformly 
expelled, as another projectile would 
have been from an ordinary pistol; and 
this expulsion is much more forcible, as 
the wis e tengo, greater as the gases 
with which the pistol barrel is filled, are 
pure oxygen and hydrogen, and in such 
proportions as exactly to produce . the 
compound, water. It is but justice to 
State, that the late lecturer, Mr. Warl- 
tire, the able assistant of Dr. Priestley, 
repeatedly noticed the fact of dampness 
or dew on the interior of the pistol after 
explosion, to the Dector; who has since 
so obstinately maintained, that water 
was in no instance formed, but simply 
separated mechanically, or chemically, 
from its various combinations. 
Second/y.—It will be, perhaps, urged, 
that in the experiment of producing har 
monic sounds in glass or tin tubes, by 
the combustion of small jets of hydrogen 
gas within them, or by the combustion of 
the philosopher’s candle covered by 
them, that the argument to be deduced 
is such as might uphold the theory of 
Dr. Jones. ‘This, however, we deny ; 
and proceed to state, what we humbly 
conceive to be the fact. 
The singular sounds produced by the 
percussion of glass, with which a small 
Stream of hydrogen gas is made to enter 
Into continuous combustion, is owing to 
a brisk vibratory motion, of the glass, 
occasioned by the successive formation 
and condensation of smal! drops of water 
on the sides of the glass tube, the air 
rushing in to replace the space or va- 
cuwm, formed by every successive pulsa- 
tion orexplosion, For though it appear 
to, the ear, fur want of a nicer power of 
discrimination, that the harmonic sound 
is continuous and uninterrupted, yet we 
have no hesitation in pronouncing it to 
be made up of a cluster of explosions, so 
rapidly succeeding eachother, as toappear 
indistinct, or the act of continuity. This 
may be illustrated by what happens in a 
the Damp in Coat Mines, 
1918 
heavy rain. It is not unusual to say, 
“Te does not rain, but it pours.” The 
purling rain isa chain of drops, so near 
each other, as to have the appearance of 
a continued stream: and again, in whirl® 
Ing a live. fire-brand swiftly round an ig- 
nited spectral circular train, or luminous 
ring, is apparent in the air]' Now we 
are certain, that this is a deceptio visus, 
an optical deception; for, we well know, 
that the ignited point of the brand is not 
in every part of the circumference of the 
apparently luminous circle at the same 
moment of time, but in ‘each degree 
of the circle successively. “Our ‘organs 
of sense, the auditory -as well as opti- 
cal, give us no just notions on these oc- 
casions, judging not from induction, but 
from apprehension, j-rception, or ap- 
pearances. The mechanical ‘causes of 
vibration in matter, whether producing 
sound, orsimple undulation, or oscillae 
tion, have been long since touched upon, 
T refer the reader, in addition to what 
is here advanced, to Lord Bacon’s Na- 
tural History. 
In places' where water is boiled by the 
condensation of aquatic vapour (or 
steam) the noise is terrific, when the 
steam is first thrown in at the bottom 
of the tub or cauldron of cold water, 
from a sufficiently copious steam-boiler 
but, as might be imagined, it becomes 
less and less loud, as the temperature is 
increased ; because the power of instan- 
taneous condensation is proportionaliy 
lessened, and; at length, when the was 
ter is heated to the temperature of boil- 
ing, or nearly so, no noise whatever js 
heard, because no ‘farther condensation 
can possibly go on. It is so too in the 
case of the harmonic sounds, which are 
consequent to the infinitely minute, but 
yet successive, explosions of the gas, or 
explosions, occurring so rapidly as not to 
be distinguished by the ear; the former 
from the subsequent. When the tin 
tube, or glass cylinder, becomes hot, 
which it wall, after some time, do, the 
sound gradually diminishes, as the water 
. formed ceases to be condensed; and 
wien the glass is of the temperature of 
212°, nosound whatever is heard. Now, 
in the case of instantaneous explosion of 
hydrégen, considerable heat is produced, 
and consequentiy, no immediate conden- 
sation can be expected; and that no such 
condensation does take place is pretty 
obvious, from: what happens in the coms 
bustion of oil, tallow, wax, and espe. 
-cially of the pure and carburetted hy~ 
drogen gases; indeed, "of all bodies whats 
ever 
