102 New Outlines of Chemical Philosophy. 
bustibles contain the element of light, which I have been induced 
to call photogen to avoid the use of ambiguous terms; and all 
those bodies, which are cailed supporters of combustion, contain 
the generator of heat, called thermogen for the same reason*. 
These elements may be made to unite and produce combustion, 
or increase the temperature of bodies, by various means, as: Ist, 
by friction; 2dly, by percussion ; Sdly, by pressure; 4thly, by 
mixture; 5thly, by increase of temperature ; and Gthly, by the 
functions of livi ing animals and vegetables. 
Thermogen and photogen in a condensed state, as in a charged . 
Leyden jar, have so strong an attraction for euch other, that they 
will pass through any of those bodies called conductors, to a very 
great disearees to be united. But, when they are united té pon- 
derable matter, they will remain mixed together for ages without 
producing any effect ; but as soon as they are brought within a 
certain distance of each other, which may be called their striking 
distance or their sphere of action, either combustion takes place, 
or the temperature of the body, in which they meet, is increased. 
The following explanations of some well known experiments 
will tend to show the importance of a theory founded on facts. 
Experiment 1. Ina Memoir read to the National Institute of 
France, M. Biot announces the important fact, that a mixture 
of hydregen and oxygen gases May be made to explode by me- 
chanical compression only, independently of the electric spark, 
Explanation. Oxygen and hydrogen gases would remain 
mixed together, for any length of time, oukthone combining, the 
thermogen and photogen which they contain being kept at too 
great a ig aS by their bases ; but } by mechanical compression 
only, they are foreed within their striking distance, and light and 
heat are produced on the same principle as combustion ‘is pro- 
duced by dischar rging a Leyden } jar. 
E xperiment 2 2. ‘Take six grains of oxygenized muriate of 
potass, and three grains of flour of sulphur, rab them together in 
a mortar, and a smart deto: rating noise will be preduced. Con- 
tinue to rub the mixture hard, and the report will be frequently re- 
peated, accompanied with vivid flashes of light. If the same 
Mixture be wi rapped in paper, laid on an anvil, and smartly struck 
with a hammer, the report will be as loud as what is usually pro- 
duced by a ] pistol. o 
E rpianalion, These experiments may be explained’on the 
same Boe ie as the last- The two ingredients, though mixed 
to gether , produced no effect until the thermogem in one of them 
anc the ph otogen in the other were forced into uion, by friction 
or perenssion, And on the same principle ‘the effects of many 
oiner iulmimating substances may be explamed. 
® See page 23, 
Experiment 
