72 

 XII. Ititelligence and Miscellaneous Articles. 



ON THE THEORY OF ELECTROLYSIS : SUGGESTION OF A 

 NEW EXPERIMENT. 



THE highly interesting experiments of Mr. Knox open new views 

 on the suhject of dynamical electricity. It would however be 

 desirable to extend the trial to all the known metals possible ; since 

 probably the power of conducting electricity through the mass will be 

 found to be different for each metal, and to be in any given case in- 

 versely as the density of the metal. The case of a current of elec- 

 tricity passing through an electrolyte is very analogous ; take water 

 as an example : so long as the particles of the fluid are extremely 

 near one another, the internal forces, or forces produced by the action 

 of the molecules on each other, are sufficiently powerful to prevent the 

 passage of the greater part of the current and consequent decomposi- 

 tion of the fluid; when, however, we mix sulphuric acid with the water, 

 the only eff'ect of which is to increase the distance between the mole- 

 cules of the water and consequently diminish the value of the internal 

 forces, the current is able to overcome those forces, and, by causing 

 the molecules of the fluid to revolve round their axis, to eftect its elec- 

 trolyzation. This reasoning suggests an experiment, which it might 

 perhaps be worth while to try. Thenard many years ago discovered 

 that phosphorus when suddenly cooled, after being heated to a cer- 

 tain temperature, becomes black, owing to some change in the ar- 

 rangement of its molecules. The internal forces at some instant, 

 whilst the molecules are passing from one state of equilibrium to the 

 other, must have passed through zero; if then this substance be 

 decomposable by electricity, it will most probably be so whilst this 

 change in the arrangement of its particles is taking place. It is 

 not unworthy of remark, that the periodide of mercury, which is an 

 exception to Faraday's law, that none but bodies consisting of a 

 single equivalent of each of their ions are electrolytes, undergoes a 

 change somewhat similar to that which takes place in phosphorus. 



V. 



ON THE FUSION OF SILICA AND CARBON. BY H. PRATER, ESg. 

 To the Editors of the Philosophical Magazine. 

 Gentlemen, 



Now that the discussions respecting the nature of carbon and si- 

 licon are going on, I beg to communicate, through the medium of 

 your Journal, a result I obtained in April 1840, viz. a fused compound 

 of silica and carbon. All that is necessary for the success cf this 

 experiment is, that the silica should be in bulk five or six times that 

 of the carbon — that the powders should be intimately mixed, and 

 exposed to a heat nearly white under sand or chalk for two or three 

 hours. 



The silica used being prepared (by Messrs. Dymond and Co.) from 

 the silicate of potass, contained, as is nearly always the case, a very 

 slight proportion of the latter, and this may have assisted the fusion ; 



