THE ACTION OF CHEMICAL AFFINITY. 
223 
main deduction. Sulphuric acid was added to a solution of acetate of copper; it 
reduced the colour greatly. The experiment was reversed, acetic acid being added 
to a solution of sulphate of copper ; it deepened the colour, but considerable excess 
of the acid was required to make a very evident difference. 
Note E. 
After my paper had been sent to the Royal Society, I observed the notice of 
M. Margueritte’s “ Recherches sur les affinites chimiques” in the Comptes Rendus, 
xxxviii. 304. He too has examined Berthollet’s vieWvS, but by means of some 
ingenious experiments totally different from those which suggested themselves to me. 
His results are in perfect harmony with my conclusions, and are just such as might 
have been deduced from the proposition of Berthollet which is quoted near the 
commencement of my paper. He finds, for instance, that on dissolving chloride of 
sodium in a saturated solution of chlorate of potash, it will take up more chlorate 
of potash ; which he naturally considers to be due to the formation of the more 
soluble chlorate of soda together with chloride of potassium. Again, chloride of 
ammonium is precipitated from its saturated solution by a very small quantity of 
nitrate of ammonia, but this does not take place when chlorate of potash has been 
mixed with it. He has obtained many analogous results. The conclusion he arrives 
at is, “ Lorsque par le melange de deux sels qui ont satisfaits a la loi d’insolubilite, il 
peut se former un sel plus soluble que le moins soluble d’entre eux, Taction de Teau 
eh determine toujours la formation dans certaines limites.” It will be seen that this 
conclusion is a particular case comprehended in my more general one. With some 
of his deductions, however, I cannot agree. He appears to have misunderstood 
Berthollet, perhaps because that chemist himself is not always consistent. He 
speaks also of an actual “ affinity of the solvent,” and of the “ force of solubility,” 
and the “ force of insolubility,” as though they were two efficient physical forces. 
On repeating some of M. Margueritte’s experiments quantitatively, I have 
obtained interesting results ; but they are not described now, as I have not yet seen 
his more extended memoir. 
