Intelligence and Miscellaneous Articles. 339 



opinion by the experiments of Dr. Schcenbein, Mr. Matteucci, and 

 Mr. Grove himself; all Avhich, as well as the experiments of Mr. Grove 

 on the inactivity of amalgamated zinc, which he proved to be due to 

 the same order of causes, have been already given in full in various 

 numbers of the Philosophical Magazine. AH the effects which have 

 generally been included under the term polarization were proved by 

 Mr. Grove to be traceable to one principle, viz. the electrolytic 

 transfer of elements having for each other a chemical affinity, and 

 the reaction caused by this affinity when the decomposing and trans- 

 ferring power, i. e. the initial voltaic current, is arrested. What we 

 are most anxious to call the attention of our readers to, are the asto- 

 nishing effects exhibited by Mr. Grove at the conclusion of his lec- 

 tui-e. Tavo batteries, little differing in construction from that de- 

 scribed 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 com- 

 pleted. 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 surprising 

 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 pro- 

 duced 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 ex- 

 hibited 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 high, and 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. 161 , and stated 

 that Mr. Pattison, who navigated the Neva with Pi-of. Jacobi in Octo- 

 ber last, had observed that the batteries employed were on Mr. Grove's 

 construction, which the Professor without hesitation admitted. 



March 20 — Mr. Schomburgk on the aborigines of Guiana. 



March 27. — Dr. Gregory on the statistics of disease and mortality 

 in London. 



LVI. Intelligence and Miscellaneous Articles. 



THEORY OF SUBSTITUTIONS. POND GAS. 



MPERSOZ sent a letter to the Academy of Sciences, relating to 

 • the conversion of acetic acid into pond gas and to the theory 

 of substitutions. The author appears to have written, lest some ex- 

 pressions made use of by M. Dumas, in the sitting of the 13th of Ja- 

 nuary, should create a belief that he had entertained the same views 

 as M. Dumas in arriving at the discovery of the production of pond 



Z 2 



