372 Miscellanies. 



2. Crosse's Galvanic Apparatus* — The public attention having 

 been much excited by the unpretending statements of Mr. Crosse at 

 the late Bristol meeting, and with the remarkable effects produced 

 by a galvanic apparatus the most extensive of any that has ever been 

 erected, at least by a private individual, we doubt not that the fol- 

 lowing letter addressed to the editors of the London Mining Journal, 

 by a gentleman so well known in science as the writer, (together 

 with the article which immediately follows,) will be acceptable to the 

 readers of our Journal. 



TO THE EDITOR OF THE MINING JOURNAL. 



Sir — Some questions having appeared in your recent numbers, 

 concerning the construction of the galvanic apparatus of Mr. Crosse, 

 I am happy in having it in my power, from having spent some inter- 

 esting days in his house, to give your correspondents an account 

 which I hope may prove satisfactory. I rejoice in the opportunity 

 thus afforded me of showing, that although locally removed, I can 

 never cease to feel a warm interest in what is passing in a county 

 endeared to me by so many associations. Each separate combina- 

 tion, forming one of the members of Mr. Crosse's galvanic series, 

 consisted of a plate of copper, containing from three to four square 

 inches of surface, bent round so as to form a cylinder, inside of 

 which was a similar plate of zinc ; round the interior zinc cylinder a 

 thin string was coiled spirally, to keep its surface, throughout, sepa- 

 rate from that of the exterior copper cylinder — these metallic cylin- 

 ders, were, in about a quarter of the series, placed in glass cylindri- 

 cal vessels, just large enough to contain them, and filled with water ; 

 but, in the greater number, the external copper cylinder being sol- 

 dered and closed at the bottom, so as to hold water itself, the glass 

 containing vessel was dispensed with. When this was the case, the 

 metallic cylinder was separated from the table on which the appara- 

 tus was placed, by the intervention of a small square of common 

 glass, a little broader than the diameter of its base ; this was done to 

 secure the insulation. These cylinders were arranged into a series, 

 in the usual form, by copper arches passing from the copper cylinder 

 of each combination to the zinc cylinder of its neighbor. The ap- 

 paratus vvhen I saw it, just after the late Bristol meeting, was com- 

 posed of eight hundred such cylinders, disposed in continuous lines, 

 so arranged as to occupy the least room.. Its effects, though excited 

 with water only, were very powerful. I should say, equal to those 



* From the Franklin Journal for April, 1837. 



