Scientific News, AccounU of BQoks,\^c. ' 239 



In order to infurc fuccefs in the exhibition of thefe experiments, Profeflbr Tromfdorf 

 remarks, that the metals fliould be rolled out very thin, though he docs not doubt that a 

 larger pile would be capable of inflaming larger mafles. 



To prove that the accenfion of the perfeft metals is a true oxidation, the experiments 

 may be performed in a hollow glafs fphere ; the oxide will then adhere to the fides of the 

 glafs, and may be colle£led. 



Profeflbr Tromfdorf is now engaged in the conftru£lion of a larger pile, confiding of 5 

 or 600 pairs of plates. 



Algemeitie Literalur ZeiiufigLXKXlV. July 16, 1 80 1. 



THE combuftion of metals by galvanifm has alfo been effi£led in a fomcwhat diff^erent 

 way by Fourcroy in Francfe. An account of this experiment was given in the Moniteur 

 about two months ago ; but as the fet to which I have accefs appears to be defe£live for 

 want, as it (hould appear, of this very Paper, I muft, for the prefent, give the particulars 

 from recolleftion. A pile of plates of zinc and filver fix inches, or more in diameter, and 

 confiding of no more than fix plates of each metal, was condru£ted in the ufual manner- 

 It gave little or no perceptible fhock, but the galvanic dream, when pafliid through fine 

 wire, ignited and difperfed it. The mod remarkable fa£t in this exhibition is, that the 

 fame furface formed into a pile with more reiterations ; as for example, when the plates 

 were cut into four, and condituted twenty-four repetitions, gave drong (hocks, but did not 

 exhibit the combudion of wire. From this curious incident we derive a law of galvanifm 

 before unknown, which is not only in itfelf very driking, but will tend to improve our 

 knowledge of the ele£tric diock, if eleftrlcity be the fame as galvanifm, or to mark their 

 differences more effedlually, if the contrary pofition fliould hereafter be rendered probable. 



Galvanic luminous Signs of the two EkSlric Powers, 



MR. Crulckfliank of Woolwich, has favoured me with an account in converfation, of 

 the flafli of light attended with noife, which he obferved many months ago, and mentioned 

 to me formerly in a letter, from which an extradl is given at page 80 of thte prefent volume. 

 The apparatus made ufe of to produce the galvanic current is there defcribed, namely, 

 two troughs, confiding each of 120 pair of plates of zinc and filver, foldered together all 

 round the edge. If the communication be made from one end of this fydem to the other, 

 by means of a wire having one; of its extremities plunged in the fluid, fo as to communicate 

 with the zinc face, and the other extremity of the wire be applied to the fluid at the end to 



which 



