168 Mr Kenwood on the Phenomena of 



identical, and it has been seen that Dr Boase has already publish- 

 ed the same view of the subject. 



We come now to the theory recently propounded by Mr Fox, 

 that veins have originally been fissures gradually opened, and 

 that they have been filled by electric action taking place between, 

 the rock masses. The idea of progressive enlargement of fis- 

 sures has been already considered when speaking of Werner and 

 Mr Hopkins. The idea of electric filling up was* first given by 

 Professor Sedgwick, who says, " after the important experi- 

 ments of Mr Fox, there can, I think, be no doubt that the great 

 vertical dykes of metallic ore, which rake through so many por- 

 tions of the county, owe their existence, at least in part, to some 

 grand development of electro-chemical power." The artificial 

 production of crystallized metallic substances from solutions by 

 the electric action of the solutions alone on each other, was first 

 discovered in France by M. Becquerel, as long ago as 1827, 

 and his experiments anticipate nearly all that has been hitherto 

 done in this country ; his list of crystalline metallic substances 

 far exceeds Mr Crossed, and they were produced by far more 

 simple means ; some account of these ingenious and important 

 discoveries appeared in an English Journal early in 1830, but 

 they have only recently attracted the general notice their import- 

 ance should have at once commanded. I may briefly offer my 

 objections to Mr Fox's theory, with a hope that the great re- 

 sources of his powerful mind, may obviate them, if worthy of 

 his notice, or the theory to embrace them if they be valid. I 

 have in the discussion of fissures stated my objection to their 

 existence, whether suddenly or progressively formed ; and I see 

 no better explanation of the horses on the one than the other as- 

 sumption. 



The salts contained in our mine water, have not been shewn 

 to differ much in the same neighbourhood, and Mr Fox (al- 

 though in one case he found 92 grains) says that they are not 

 generally more than from one to five grains in a pint. Beside, 

 we have yet to learn that these solutions, or any others, will de- 

 telope electricity in rock masses ; Mr Fox's beautiful discovery 

 of electric currents in veins, being confined to the veins alone, 

 for neither in his experiments (yet published) nor my own, have 

 we ever detected electric currents in the rocks or in the earthy 



