1817.] an Influence on Chemical Action. 353 
action. Now I think the explanation of those phenomena which 
these chemists have endeavoured to show to proceed from the above 
cause, is unsatisfactory, and probably they may be explained on 
another principle. We find, by taking a compound of two ingre- 
dients, A and B, and between which there is a greater affinity than 
either A or B possess for C, that,. by adding C in a small quantity, 
no decomposition takes place ; but by adding C in a larger quantity, 
it effects a decomposition between A and B, and unites with either 
A or B. Those chemists who maintain that the quantity of matter 
has an influence on chemical action explain the above as follows: 
they say it is owing to the largeness of the mass of C, and that C in 
this case exerts a greater power in consequence of its mass being 
increased. Now I would ask, but with all deference to the opinions 
of those chemists who maintain the above doctrine, if it might not 
be produced from the following cause? Instead of making use of 
imaginary bodies, I will take two instances of chemical combination 
to illustrate my meaning. The first is a resinous gum dissolved in 
alcohol ; the second, antimony dissolved in muriatic acid. If to 
either of these solutions we add a little water, a precipitation takes 
place; but immediately upon agitating the mixture, the precipitate 
is redissolved ; by adding a considerable quantity of water, the pre- 
cipitate‘is again formed, but will not again be dissolved. It appears 
to me that it is not owing to any peculiar attraction which the larger 
quantity of water exerts for the spirit in the first instance, and the 
acid in the second, that the precipitate is formed; but that the 
water merely acts as a-diluent; the first portion we add dilutes it to 
a certain degree, but still not so much as to prevent its dissolving 
the given quantity of resin or antimony; but by diluting it more 
largely, it becomes incapable of holding the ingredients in solution. 
We could not dissolve the antimony in the acid largely diluted; and 
so we may infer that the acid thus largely diluted becomes incapable 
of holding in solution the portion of antimony which it took up 
when in an undiluted state. It is, as every chemist knows, a 
general law, that before chemical action can take place between two 
or more bodies, they must be in contact. By contact I would be under- 
stood to mean the nearest points at which bodies approach to each 
other; whether they actually touch is a matter of speculation ; and 
_ with regard to the subject under consideration, it is not necessary to 
enter on this point. In fact, the particles of the muriatic acid are 
removed to a distance from the particles of the antimony, and that 
‘degree of contact of the two which is necessary for chemical action 
is destroyed. I conceive that, were it possible to bring the particles 
of the muriatic acid in contact with those of the antimony, not- 
withstanding they were in the midst of the water, a union would 
take place, and no decomposition be formed. It is now generally 
believed that in combination one atom of this body unites with one, 
two, or more atoms of the other body. So we may suppose that the 
water produces a decomposition 7! removing the necessary number 
Vor, 1X. N° V. 
