24 New Outlines of Chemical Philosophy. 
thermogen is heat; they are the generators of light and heat, 
light and heat being the effects which they produce on matter. 
The thermogen on the inside of a charged jar cannot be felt, 
nor does it produce any effect upon the most delicate therme- 
meter, nor is any light perceptible on the outside of the jar. But 
let the jar be discharged through a piece of iron wire, and both 
light and heat are produced. When the metal becomes red hot 
by this means, it loses its photogen, attracts oxygen gas from 
the air, and becomes oxidized. If this oxide be mixed with 
some matter containing photogen, and heat applied, oxygen gas 
will be reproduced, and the metal will receive photogen, and _ 
again become malleable. 
The application of these elements, to elucidate some of the 
most interesting phenomena in nature, will be move fully treated 
of hereafter, 
Composition of Water. 
Some philosophers maintain that water is a simple body, and 
the only ponderable basis of oxygen and hydrogen gases, and other 
aérial fluids ; but others “inp that water is a compound of 
oxygen and hydrogen, and this opinion is now generally adopted 
by writers on chemistry. But all the experiments made to se- 
parate the component parts of water, tend to prove that it is a 
body simple and undecompounded. What has led men to con- 
clude that water is a compound body, seems to have arisen from 
their supposing that the electric spark is a simple fluid; but as it 
is now well known that it consists of two elements possessing 
different properties, both chemical and mechanical*, the passing 
of these elements through water is no proof of its being a com- 
pound substance, notwithstanding oxygen and hydrogen gases 
are produced by this means. 
When thermogen and photogen pass through water in con- 
trary directions, thermogen and water form oxygen gas; pho- 
togen and water form hydrogen gas. These gases being’ mixed 
together in a close glass vessel, and their temperature increased 
to a certain degree, combustion takes place, light and heat 
escape through the glass, and the product is pure water. 
That thermogen and photogen are capable of producing com- 
bustion, before they entered the water, is unquestionable, nor 
can it be supposed that they are annihilated by passing through 
it; for they appear again in the two gases, producing the same 
phenomena of light and heat as_before. Hence it appears that 
the two elements which compose the electric spark are the impon- 
derable elements of the two gases, and that water is their com- 
mon base. Oxygen and hydrogen gases thrown upon fire pro- 
* Phil. Mag. vol. xlii. p, 161. . 
duce 
