438 Comparison of the Old and New Theories [Junu, 
bined with twice as much oxygen as in muriatic acid. This gas 
explodes in a heat of between 86° and 104°. Fire is produced, and 
the gas occupies 14 times the volume which it formerly occupied, 
being resolved into } oxygen and 3 oxymuriatic acid gas. I explain 
these appearances in the following manner :—Muriatic acid com- 
bines ata certain low temperature less intimately with two atoms of 
oxygen, with which it makes its escape as a gas from the liquid. In 
this compound the electro-chemical polarization of the oxygen is 
less completely neutralized than in the compound of muriatic acid 
with half as much oxygen in oxymuriatic acid gas. When the 
temperature is elevated, the muriatic acid cannot retain the whole 
of the oxygen ; it therefore enters into a more intimate combination 
with one half of it, and undergoes a combustion into oxymuriatic 
acid, fire being evolved in consequence of the more complete 
electro-chemical neutralization. ‘The other half of the oxygen is 
set at liberty. The separation of this portion has no other effect 
upon the explosion than that of increasing the volume of the gaseous 
mass, and consequently the energy of the explosion. 
This explanation appears at first sight liable to two objections. 
The first is, that the muriatic acid, which was here in the state of a 
hydrous acid, should separate from the water to unite itself in an 
elastic state with two proportions of oxygen less intimately com- 
bined. But it isa very common appearance when a gaseous or 
insoluble body is formed by the play of affinities for the liquid body 
to remain while the gaseous body disappears, or is precipitated from 
the liquid, though its formation be owing to a weaker affinity. The 
muriatic acid here leaves the water, which should have retained it 
in order to combine with oxygen, and form euchlorine. In the 
same way concentrated phosphoric or arsenic acid separates the 
much stronger sulphuric acid from its bases whenever the mixture 
reaches the temperature at which anhydrous sulphuric acid becomes 
gaseous. Chemistry can exhibit many such examples. The expla- 
nation of them belongs to a department of the doctrine of heat still 
unexplained, and to its relation to both the electricities. The ex- 
planation furnished here by the old doctrine affords no anomaly 
different from what takes place in other bodies. 
The second apparent objection is, that the muriatic acid com- 
bines less intimately with two portions of oxygen than it does with 
the one portion with which it constitutes oxymuriatic acid. But it 
is clear that, provided the same difference in the intimacy of com- 
bination takes place between other bodies in different states, this 
explanation will furnish no objection or improbability. I will now 
show that such a difference in the intimacy of compounds is a very 
general appearance, which takes place not only between simple 
bodies, but likewise between compounds, to which hitherto but 
little attention has been paid. 
When, in the year 1811, I was occupied with examining the 
combinations of antimony, I discovered accidentally that several 
metalline antimoniates, when they begin to grow red-hot, exhibit 
Ee 
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