104 Prof. W. Ostwald's Electrochemical Researches. 



the positions of dots and lines, to complete the curve to a 

 certain degree of approximation. If, however, a greater 

 accuracy be needed, all we have to do is to diminish the an- 

 gular distance between the circuit-closers, and to increase 

 their number. In the next instrument to be made, I am going 

 to introduce a few improvements, of which the most important 

 is the mode of arranging the circuit-closers and capillary 

 plates. Instead of having the circuit-closers movable with 

 the coil, and capillary plates fixed, we may arrange so that 

 the capillary plates move with the coil, while the circuit-closers 

 are kept stationary ; and by this means, it is possible to di- 

 minish the angular distances between the circuit-closers, and 

 to increase their number without increasing the moment of 

 inertia of the needle, and thus to obviate the above defect to 

 a great extent, and, at the same time, to give to the instrument 

 a greater sensibility. 



XIII. Electrochemical Researches. By W. Ostwald, Pro- 

 fessor of Chemistry in the Polytechnic School, Riga*. 



A 



LL reactions of acids, dependent on the characters, rather 

 than on the nature of the constituents, of the acids, 

 occur with an intensity which is different in each case, but is 

 always proportional to an affinity- constant which is itself 

 dependent only on the character of the acid and not at all on 

 the nature of the reaction. This fundamental fact, which 

 throws new light on the old conception of affinity-constants, 

 has been proved by the author for various reactions ; viz. the 

 formation of salts in aqueous solutions, the actions of acids on 

 insoluble salts, the change of acetamide into ammonium ace- 

 tate, the catalytic decomposition of methylic acetate, and the 

 inversion of cane-sugar f. These reactions, some of which 

 are statical and others kinetical, led to the same numerical 

 values for the affinity-constants of the acids examined. 



Adopting Clausius's theory of electrolysis, and Williamson's 

 theory of chemical change, a distinct connection must exist 

 between the reactions of acids and the electrical conductivity 

 of these acids- The theory of Williamson supposes that a 

 continual exchange of atoms is occurring among the reacting 

 molecules ; the velocity of a chemical action must therefore 

 depend on the velocity of the atomic interchanges. The theory 

 of Clausius says that electrolytic conduction is effected so 

 that the free ions continually displace equivalent elements or 



* Abstract of Prof. Ostwald's recent work, prepared by himself, and 

 communicated by M. M. Pattison Muir, Cambridge. 



t See Pattison Muir's ' Principles of Chemistry/ p. 418 et seq, 



