1816.] respecting the Nature of Oxymuriatic Acid. 43} 
trical polarization takes place between them, which increases as 
their temperature approaches nearer to that in which their peculiar 
affinities can act, when the polarization vanishes at the same time 
that their union is completed, with the appearance of fire. Sucha 
polarization, therefore, must take place between the oxygen and 
hydrogen in fulminating silver; and it must be the greater the less 
of their original electro-chemical properties is neutralized in the 
other compound. Experience likewise teaches us that the affinities 
are more active in solid and liquid bodies at low temperatures than 
in gases; and that they act in condensed gases more readily than in 
gases of the usual density. * 
From all these observations it may be concluded that in fulmi- 
nating silver the polarization is nearly at its maximum (that is, at 
the discharging or uniting point), so that a very small cause will 
bring it to that state. Hence we see the reason why a small touch 
will make fulminating silver explode, either from the elevation of 
temperature, or from the power which friction has to excite elec- 
tricity. But whence comes the extraordinary rapidity with which 
the decomposition takes place? Can it be explained by the rapid 
communication of the high temperature, or the combustion? Ex- 
perience teaches us that the propagation of heat is not particularly 
rapid, and that it is very far from instantaneous, even in liquid 
bodies. The rapidity increases with the increase of temperature, 
but it always requires time. By the mere propagation of heat gra- 
dually evolved by combustion, it is impossible to explain the im- 
measurable rapidity of an explosion by which a cannon is burst 
before the ball has time to be put in motion. On the other hand, 
experience shows us that the propagation of electricity may be con- 
sidered as instantaneous. In the exploding compound there are two 
or three bodies almost at a maximum of electrical excitement, 
Hence we may conceive how this excitement discharges itself at 
once in an immeasurably small period ; and by the combination of 
substances which at that temperature are gaseous, the dreadful 
phenomenon which we call explosion may be explained. 
The electro-chemical theory, then, explains all the appearances 
of an explosion in a satisfactory manner, and corresponding with 
all the rest of chemical science. It shows us that an explosion 
cannot take place unless when a compound (or a very complete 
mechanical mixture) can arrange its constituents in other propor- 
tions, by means of which their opposite electro-chemical properties 
can be much more completely neutralized than before. 
But now the question occurs: as in each chemical combination 
an increase of temperature takes place, which often amounts to 
fire, does the same take place in opposite circumstances, or during 
chemical decomposition? We have no theoretical ground to deny 
this. We are ignorant whether fire consists in electrical discharges; 
* Forexample, fulminating air is not set on fire by a red-hot a cd but it takes 
fire of itself when it is strougly compressed, 
