VOLTAIC REACTION. 235 



each other a chemical affinity, and the reaction caused by 

 this affinity when the decomposing and transferring power, i.e. 

 the initial voltaic current, is arrested. What we are most 

 anxious to call the attention of our readers to are the effects 

 exhibited by Mr. Grove at the conclusion of his lecture. Two 

 batteries, little differing in construction from that described 

 by him in the ' Lond. and Edinb. Phil. Mag./ were charged 

 some time previously to the lecture, and up to the period of its 

 conclusion remained in perfect inactivity until the circuit was 

 completed. One of these was arranged as a series of five plates, 

 and contained altogether about four square feet of platina foil ; 

 with this the mixed gases were liberated from water at the 

 rate of one hundred and ten cubic inches per minute. A sheet 

 of platinum, one inch wide by twelve long, was heated in the 

 open air through its whole extent, and the usual class of 

 effects produced in corresponding proportion. With the other 

 arrangement, consisting of fifty plates of two inches by four, 

 arranged in single series, a voluminous flame of one inch and 

 a quarter long was exhibited by charcoal points, which showed 

 beautifully the magnetic properties of the voltaic arc, as Dr. 

 Faraday held a piece of iron near it, being attracted and 

 repelled by different portions of the iron : 'bars of different 

 metals were instantly run into globules and dissipated in 

 oxide. It should be borne in mind that all these effects were 

 produced by a battery which did not cover a space of sixteen 

 inches square, and was only four inches highland which had 

 been charged for some hours. 



Mr. Grove adverted to the letter of Prof. Jacobi to Dr. 

 Faraday published in ' Lond. and Edinb. Phil. Mag./ vol. xv. 

 p. 1 6 1, and stated that Mr. Pattison, who navigated the Neva 

 with Prof. Jacobi in October last, had observed that the bat- 

 teries employed were on Mr. Grove's construction, which the 

 Professor without hesitation admitted. 



