rt Proceedings. 
Balfour Stewart, Esq., read a paper on “Certain laws observable 
in the mutual action of Sulphuric Acid and Water.” He remarked 
that these two liquids combined in any proportion, and seemingly 
without any reference to chemical equivalents; but he would ex- 
hibit a method by which a distinct reference to their equivalents 
might be discerned. If we calculate the specific gravities of the 
different strengths in Dr. Ure’s table, viewed as composed of strong 
sulphuric acid of the specific gravity 1°8485 and water, we shall find 
that these are less than the observed specific gravities given by Dr. 
Ure. This condensation is due to chemical action, and its proportion 
is greatest for strength 73, which denotes a chemical compound of 1 
equivalent sulphuric acid, and 2 equivalents of water. But we 
may take any strength of mixture as our standard, and view all 
other mixtures as composed of this mixture, and sulphuric acid, or 
the same mixture and water according as they are stronger or 
weaker. In this way, adopting the specific gravity of the standard 
given by Dr. Ure, we have a different set of calculated specific 
eravities for each different standard, and consequently a different 
proportional condensation. If we take the strength 40, 45, 43 as 
standard, we are pointed to the maximum of condensation at 
strength 73 as before, but if we take as standards strengths 40, 55, 
53, we are pointed to a maximum of condensation between strength 
84 and 85 which denotes one equivalent of sulphuric acid, and one 
equivalent of water. In like manner if we take as standard strengths 
40, 38, 45, we are pointed to a maximum at strength 82, which 
probably denotes a compound containing 5 equivalents of sul- 
phuric acid, and 6 equivalents of water. Mr. Stewart, in con- 
clusion, observed that he did not so much regard the immediate 
results of this investigation as-the means it afforded us of tracing 
definite chemical action in cases of solution as well as perhaps in 
alloys and amalgams, 
The Rev. A. Morison observed that the subject had no con- 
nexion with the Atomic theory, as Mr. Balfour Stewart seemed to 
imply, nor is it apparent that any result of importance would be 
gained by the attempt. It is the production or suggestion rather 
of a mathematical than a chemical mind. In it, the mathema- 
tician subordinates the chemist, whereas the reverse is the order 
of the practical man. 
Mr. Stewart agreed that there was no electric affinity in the 
combination of sulphuric acid and water. The object of the paper 
was to show that a change was effected by solution, and that that 
change was regulated by the principles of the Atomic theory. In 
chemistry the compounds are very often entirely different from 
either of their in&redients, often slightly different; but in cases of 
solution it has been the habit to consider that no chemical action 
has taken place at all. It is not necessary that the compound 
should possess different optical properties, or differences which are 
obviously apparent in order to constitute chemical action. The 
test of contraction in volume is surely quite legitimate. 
