TRANSACTIONS OF THE SECTIONS. 47 
_ appear upon the negative plate; and, after some weeks of continued 
action, small veins of crystalline lead will be found permeating the 
_ mass of plaster of Paris in an exceedingly elegant and arborescent 
form. Similar results are obtained when plates and solutions of zinc, 
tin, antimony, silver, and many other metals, are substituted for those 
of copper and lead. These experiments, moreover, are by no means 
_ liable to failure from slight causes, the results being always constant. 
_ Having thus proved that well-defined crystals of metals are ob- 
tained, if sufficient time is allowed, by allowing a current of the 
_ feeblest intensity to permeate a porous substance, imbued in a metallic 
_ solution, without the presence of poles or supposed attracting points, 
_ Dr. Bird was anxious to ascertain how far this process might be 
applied to the artificial fossilization of wood, by injecting (as it were) 
_ by voltaic action, every part of its permeable tissue with crystalline 
_ metals. Some few experiments on this head, which he has performed, 
seem to promise the most perfect success ; and the author hopes to 
_ present an account of the results to the next meeting of the Asso- 
ciation. 
A. The exterior cylinder containing brine. 
B. The inner cylinder containing the metallic solution. 
C. The copper electrode on which metallic crystals are formed. 
‘Mam Z. Zinc or positive electrode. 
IN Ii P. The thick plaster plug, (closing the cylinder B,) in which 
nn veins of the crystalline metals become formed by the pas- 
sage of the current from Z. to C. 
il 
On the formation of Crystallized Metallic Copper in the shafts of the 
__ Cronebane Copper Mine, County Wicklow, Ireland, and of native 
Sulphate of Iron and Copper on the same locality. By R.Mazer, 
MRLA. 
___ Metallic copper has been frequently obtained, as is well known, by 
various methods in the laboratory, and in large masses in Daniell’s 
- Constant Batteries; but the present is the first occasion on which 
_ native copper has been found, actually detected, as it were, in the very 
act of formation in the mine shaft. 
_ The Cronebane mine has been wrought for a very lengthened period, 
and has an additional interest as connected with the present subject, 
_ from the electro-magnetic condition of the next mine to it, the Con- 
_ noree, which is part of the same vein, having been determined by Mr. 
_ Petherick. (Philosoph. Mag. 3rd Series, vol. iii.) He found it de- 
flected the galvanometer needle 18°—that the ore was negative, and 
_ the ground positive. The lode is situated in clay slate, dipping to the 
