218 
DR. GIjADSTONE on CIRCUMSTANCES MODIFYING 
will necessitate a fresh distribution, and so on. Thus a state of things will ensue 
analogous to what is observed where one of the salts is so sparingly soluble as to 
separate by crystallization ; great dilfiisibility will compensate for weak affinity ; and 
the mutual attraction of the two components of the more diffusible salt will always 
be exaggerated. 
The testimony of Malaguti’s experiments. — Malaguti* examined the present 
question by taking two salts, both of which were soluble in water, but only one of 
wliich was soluble in alcohol, mixing them in equivalent proportions in water, and 
then pouring the aqueous solution into a large quantity of alcohol. Some of the 
resulting salts were precipitated, others remained in solution; and the proportion in 
which one acid divided itself between the two bases was thence ascertained. This 
afforded him the data for determining what he denominates “coefficients of decom- 
position,” a large number of which are tabulated ; yet he attached no importance to 
the absolute value of these coefficients on account of the objection that, if there be 
really four salts in the aqueous solution, their proportions may change when they are 
thrown into alcohol. However, on considering these experiments, three important 
results may be arrived at : — 1st, that two salts on being mixed resolve themselves into 
four ; 2nd, that this partition takes place in a definite manner; 3rd, that the propor- 
tions of the resulting salts are independent of the manner in which the different 
elements were originally combined-f'. 
The testimony of substances acted on by one of the compounds liberated in a mixture 
(f salts. — It is to be expected that if two binary compounds be mixed, the formation 
of a new compound, though it remain in solution, may often be ascertained by certain 
chemical powers which it is capable of exerting. Instances of this are not wanting. 
Thus gold, as every one knows, is not attacked by hydrochloric or nitric acid singly^ 
but is dissolved by a combination of the two; neutral potash salts of course have no 
action upon it ; and yet gold dissolves readily in a mixture of either nitrate of potash 
and hydrochloric acid, or of chloride of potassium and nitric acid ; whence it appears 
to me the conclusion may be fairly drawn, that in both mixtures the potash relinquishes 
a portion of the acid with which it was originally combined, or (which is the same 
thing) that it divides itself between the two. . 
Such experiments as this have no quantitative value, since the liberated substance 
immediately enters into a new combination, which must give rise to a fresh distribu- 
tion of the different elements, and so on until no more of the active substance can be 
|)roduced. A mere solvent action of the liberated body would be preferable to an 
action where positive chemical combination or decomposition takes place; but such 
cases scarcely exist. Among the actions which appear to answer this requirement 
most fully, is vffien a salt insoluble in water is dissolved in an acid, as for instance, 
* “ Exposition de quelques faits relatifs a Faction reciproque des sels solubles,” Ann. de Chim. et de 
Phys. 3. t xxxvii. p. 198. 
t See Note E. 
