THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE, 



[FOURTH SERIES.] 



AUGUST 1851. 



XVI. On the Measurement of Chemical Affinitij. 

 Bij Isaac B. Cooke*. 



THE controversy in reference to the source of voltaic electri- 

 city, appears to be decided, at least in England, in favour 

 of tlie chemical theory. A voltaic current seems generally ad- 

 mitted to be nothing else than the circulation, in another form, 

 of the sum of the chemical affinities developed in the circuit. 

 Is it not therefore time, since electric currents are susceptible of 

 minutely accurate measurement, that an attempt was made to 

 analyse the forces circulating in our batteries, and to assign to 

 the different substances present the value of the respective affi- 

 nities they mutually exert, from the united action of which 

 results that balance of forces constituting the effective power of 

 the battery ? 



Accurately to measure and tabulate the combining force of the 

 constituents of compound substances, as we now do their com- 

 bining quantities, specific gravities, &c., would be an important 

 step in chemical science, and a great addition to our know- 

 ledge of the natural histoiy of the materials of the globe. 



Many attempts have been made roughly to estimate these 

 forces by purely chemical experiment ; and tables have been con- 

 structed of the strength of affinities, in which, without nume- 

 rical values, substances have been arranged, with more or less 

 accuracy, in the order in which they expel each other from their 

 combinations. Estimates have also been formed, founded on 

 other considerations, but with little pretensions to numerical 

 exactness. Accurate measurements, again, have been made by 

 several methods, and by various observers, of the intensities of 

 current developed in different voltaic arrangements, and with 

 * Communicated by the Author. 



Phil Mag, S. 4. Vol, 2. No. 9. Aug. 1851. H 



