SS8 Royal Institution : — Mr. Grove on Voltaic Reaction. 



bismuth to silver ; or if the hydro-sulphuret of potash be used, it is 

 from bismuth to silver, and from silver to antimony ; and, finally, 

 if strong muriatic acid be used, it is precisely the reverse, or from 

 antimony to silver, and from silver to bismuth. The inconsistency 

 of these results with the contact theory is then insisted on and 

 further developed. 



The last section of this series is on the improbability of there ex- 

 isting any such force as the assumed contact force. The author 

 contends that it is against all natural analogy and probability that 

 two particles which, being placed in contact, have by their mutual 

 action acquired opposite electrical states, should be able to discharge 

 these states one to the other, and yet remain in the state they were 

 in at the first, i. e., entirely unchanged in every point by what has 

 previously taken place ; or, that the force which has enabled two 

 particles by their mutual action to attain a certain state, should 

 not be sufficient to make them keep that state. To admit such ef- 

 fects would be, he thinks, to deny that action and reaction are 

 equal. The contact theory, according to him, assumes that a force 

 which is able to overcome powerful resistance, both chemical and 

 mechanical, can arise out of nothing. That without any change in 

 the acting matter, or the consumption of any other force, an electric 

 current can be produced which shall go on for ever against a con- 

 stant resistance, or only be stopped, as in the voltaic trough, by the 

 ruins which its exertion has heaped in its own course ; — this, the 

 author thinks, would be a creation of power, such as there is no 

 example of in nature ; and, as there is no difficulty in converting 

 electrical into mechanical force through the agency of magnetism, 

 would, if true, supply us at once with a perpetual motion. Such a 

 conclusion he considers as a strong and sufficient proof that the 

 theory of contact is founded in error. 



FRIDAY-EVENING "MEETINGS AT THE ROYAL INSTITUTION. 



January 24, IS-iO. — Mr. Faraday on voltaic precipitations. 



January 31. — Dr. Grant on the structure and growth of corals. 



February 7. — Mr. Faraday on a particular relation (Dove's) of 

 condensable gases and steam. 



February 14. — Mr. Catlin's account of his residence and adven- 

 tures among the native tribes of North America, with notices of 

 their social condition, customs, mysteries, mode of warfare, tortures, 

 &c. 



February 21. — Mr. Nasmyth on the origin of alphabetic charac- 

 ters, and on the pneumatic mirror. 



February 28. — Mr. Brayley on the application of science to the 

 choice of building stones, with reference to the selection of stone 

 for the New Houses of Parliament. 



March 6. — The Rev. Mr. Hincks on the monstrosities of plants. 



March 13. — Mr. Grove on voltaic reaction, or the phfenomena 

 usually called polarization. 



Mr." Grove detailed the first experiments of Volta, Erman, Ritter, 

 and Davy, the more recent ones of De la Rive, the explanation of 

 these by Becquei^l, and the confirmation of this latter philosopher's 



