11 



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 

 mi^dit be discerned. If we calculate the specific gravities of the 

 difi'erent 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 sarne 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 

 gravities 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 50, 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 Eev. 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 afiinity 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 ingredients, 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. 



