148 
ON CHEMISTRY. 
fathom. Nature affords irrefragable evidence of the all prevailing, 
all actuating principle of elementary fire, a principle that can alone 
he rationally referred to the Sun. I cannot, however, dwell now 
upon any inquiry into the facts that give substance to the hypothesis 
which, I fear has been of late, but too little investigated. The sub¬ 
ject will be resumed when I come to consider the phenomena of light, 
heat, and electricity. As few readers can be supposed to possess an 
apparatus, by which they may bring the foregoing experiments to 
the test, I shall mention another, far more simple and of easy per¬ 
formance, that may afford some ready proof of the compound, de¬ 
composable, nature of atmospheric air. 
Pour a quantity of water into a flat dish, let a small saucer con¬ 
taining a little lamp oil, and a cotton wick be made to float on the 
water; by the side of the saucer fix a stand of any sort that can sup¬ 
port a piece of wax taper, p so that its wick may rise two or three 
inches above that of the lamp, then adapt a tall bell-glass to the dish, 
large enough to permit it to cover the saucer and taper, and to leave 
a space of an inch or more between them and the glass. The height 
of the bell ought to he such as to leave six inches clear space above 
the taller wick. The apparatus being thus prepared, light the two 
wicks, cut each of them, if needful, till the flames appear well defined 
and without smoke, and then invert the bell-glass over both. Its 
lower edge will now be immersed in the water of the dish, and thus, 
air will be entirely excluded. For a time, each will emit its usual 
light, and at first will produce expansion of the air within, so that 
the operator ought to press gently, but steadily, upon the top of the 
glass to keep it from falling, with his hand guarded by a cloth, to 
prevent accident in case of a sudden fracture. By the attractive 
energy exerted between the combustible bodies, and the supporting 
principle of the air, (the oxygen gas,) all, or the greater part of the 
latter will be separated from the other component gas, and unite with 
the components of the cotton, oil, and wax. Water and some carbo¬ 
nic acid will be formed; the former will be deposited chiefly in the 
dish, and the latter will also, in part, combine with the water, as that 
fluid and carbonic acid have some affinity for each other. In pro¬ 
portion as the supporting principle is withdrawn, the flames of the 
wicks will grow smaller, but that of the taper will, in most instances, 
be first extinguished, owing to the superior weight of the purer air. 
As, however, carbonic acid is still heavier, the quantity produced by 
the taper may perhaps descend, and put out the flame of the lamp. 
When both have expired, it will be evident that, the air remaining 
in the bell-glass can no longer be capable of supporting combustion ; 
