Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/466

Rh ON THE COKDITIONS OP MATTKK. 453

above the fluid on the other ; this is the well known exosmose always observed during electro-chemical action. But in this case the mass of clay was elevated on the same side, and this went on increasing until the fluid was dried off. This may have been merely mechanical, but the fact is* curious in itself and worthy of notice as it may lead to the explanation of some movements of solid matter under circumstances of apparent difficulty. Other experiments have proved to me the possi- bility of raismg comparatively large masses of matter by the agency of current force or the dynamic power of voltaic electricity.

48. A number of nodules were formed in the clay in this instance, and it is curious to observe that all these concretions arrange themselves along the line of the current. In nature they are mostly found in some given direction parallel to each other ; and, from the indications we have thus obtained, it is probable that we shall find their order deter- mined by some local electrical influence.

49. A thin paste of plaster of Paris was placed between similar plates of zinc and copper, which were excited by diluted sulphuric acid. This action was kept up for about three monllis, and then allowed to dry off. On becoming quite dry, it was found that the gypsum was laminated to the depth of an inch on the zinc side and indurated considerably on the copper side.

50. An ordinary Bath brick used for scouring cutiery — ^a siliceous sandstone — ^was placed between a zinc and copper plate, in a similar voltaic arrangement to those already described, the current being ex- cited |by a solution of salt (muriate of soda) on the zinc side, and sul- phate of copper on the copper side. The lamination was very decided to the depth of more than half an mch, from which, to the middle, the brick remained unchanged, whilst on the copper side the general indu- ration had taken place, as in the other examples. Copper had passed through the brick, and it presented itself in the form of carbonate on the zinc side, running across the lines of lamination. This brick had been placed in the trough vertically ; it was only on one side that the carbonate of copper was seen, but it extended from a certain point near the centre of that side, increasing in quantity towards the zinc plate, BO trace of it being seen on any part of the brick, near the copper plate, except a thin lamina of it between the plate and the sandstone. As the laminae dried, they became very much contorted, and were gradually broken off from the mass.

51. A similar brick was placed horizontally between a copper and a xinc plate, excited as before.. After the action of about four months, it was dried, when it was found to have cracked from near the bottom of the zinc plate to the top of the copper plate, separating into two nearly equal parts. This fracture corresponded in direction very nearly

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