200 Miscellanies. 
taic agency, but also in imparting to the clay a laminated or schistose 
structure; the veins and lamine being perpendicular to the voltaic 
forces. In some instances only a pair of plates, or in preference cop- - 
per pyrites and zinc, were employed to produce the voltaic action; 
but a constant battery consisting of several pairs of plates was much 
more effective. Among the veins thus produced in clay, Mr. Fox 
mentions oxide and carbonate of copper, carbonate of zinc, oxides of 
iron and tin. Veins of carbonate of zinc were formed, sufficiently 
firm to admit of being taken out in plates of the size of a shilling. 
Mr. Fox then describes a vein formed in pipe-clay, by Mr. Jordan, 
by five pairs of cylinders, in three weeks. The clay divided an earth- 
enware vessel into two cells, in one of which, containing the cop- 
per plate, a solution of sulphate of copper was put; and in the oth- 
er, or zinc cell, a solution of common salt. Well-defined veins were 
thus produced of carbonate and oxide of copper, and carbonate of 
zinc, parallel to the laminz into which the clay divided; as well as 
another of carbonate and oxide of copper at right angles to them. 
On dividing the mass of clay in the direction of the principal hori- 
zontal vein, the carbonate of zinc was found on the negative side, or 
towards the copper plate: and the carbonate of copper nearest the 
zine plate: and as the former must have been derived from the zinc 
plate, it is curious to observe such a complete transposition of the 
respective metals. 
Mr. Fox is of opinion that these results have a strong bearing on 
the numerous mineral veins and beds which are found conformable to 
the direction of the lamine of the containing rocks, as well as on 
those veins which traverse the laminz of the conformable veins —1- 
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