f 349 J 
. EXXUI. New Outlines of Chemical Philosophy. By Ez.WaLkER, 
Esq. of Lynn, Norfolk. 
[Continued from p. 285.] 
On Light and Heat. 
Sirs, EEO theory of combustion is founded on the 
supposition, that in every case oxygen combines with the burn- 
ing body, and that the weight of the product of every body after. 
combustion corresponds with the weight of the body before 
combustion, plus that of the oxygen consumed. 
But this theory is questionable, for no account is taken of 
the light and heat generated in the process. If a long mould 
candle, which weighs two ounces troy, be lighted, and placed to 
form an angle with the horizon of 60 degrees, it will be so per- 
fectly consumed as not to leave a single grain of ashes; the 
only product being pure water. 
I have observed in a former paper, that oxygen gas is com- 
posed of thermogen and water*, so that, when thermogen com- 
bines with the burning body, the base of the gas being incom- 
bustible becomes the product. : 
Now, the important problem to be investigated is, what be- 
comes of the two ounces of matter of the candle? Is it con- 
verted into light and heat, or is it transmuted into pure watef? 
Now, unless it can be demonstrated that tallow, oil, and wax 
are transmutable into pure water, the theory of combustion of 
M. Lavoisier falls to the ground. 
It is well known that a charged Leyden jar contains nothing 
that is either tangible, visible, or ponderable; but let it be dis- 
charged through the air, or some other conducting substance, 
and both light and heat will be generated; nor can either light 
or heat be produced, unless the two elements of combustion be 
united to ponderable matter. Consequently, light is a triple. 
compound of thermogen, photogen, and combustible matter ; 
and heat is a compound of the same two elements united to 
matter of the same kind, but differently modified. 
As light comes from the sun in seven seconds and a half, it, 
therefore, passes over five miles in about =,4,,tht part of a 
second of time. A candle which weighs two ounces troy will 
burn about ten hours, consequently ~3,tht part of a grain will 
* Page 24 of this volume. 
A Miles. Bass ie Miles 450% 5 ” 
+ As 95,000,000 :7 30 (450 His FS * 95,000,000 ='0000 2+ =s5900 ofa 
second. 
He. Oz 
$ As10:2:; 50350 isto of a grain, 
be 
