■Scitnt'tfic NewSy Accounti ^ Books, i^c. 319 



was made part of the circuit j and fince making that obfervatlon they conftantly armed the 

 extremities of theit conductors with gold leaf; by which means they obtained with eafe a 

 ftrong fpark, and ufed the fame method with the greafeft fuccefs in fetting fire to phof- 

 phorus, fublimed fulphur, fulminating gas, and gunpowder, the latter of which is not 

 eaCly fired by the electric fluid. It was remarked,, that in thofe experiments the portion 

 of gold leaf which covered the extremity of the condu£lors, was Itfelf fufed and reduced 

 into a globule more or lefs perfe£l:, according to the force of the fpark. 



They repeated my experiment with the condenfer, and found agreeably to what I had! 

 obferved, that the filver is in the negative ftate,. and the zinc pofitive. By the interven- 

 tion of the condenfer they charged a jar, but could not obtain the flighted galvanic com- 

 motion. But by means of two condenfers (by the procefs of doubling I fuppofe) they re- 

 peated upon the EleCtrophore the experiment of producing the figures of Lichtenberg, with 

 the fame varieties and forms which would have been produced by the eleftric fluid. 



Dr. Grapengeifler has applied the galvanic energy in the courfe of medical praftice, anA 

 obferves, that the fimilitude of this ailion with that of the ele£lric fluid cannot be miftakenv 

 but thefc philofophers think, that a great diflimilitude, or variation in thefe two powers,, 

 vas indicated by an experiment they made of infulating the whole apparatus, together with 

 the tube in which the procefs of decompofing water was going forward. In this fituation 

 they ele£triGed the whole apparatus by the common machine, and obtained very confide- 

 rable fparks, without producing any change In the phenomena between the wires in the 

 tube. Hence they think that thofe powers may be imagined to be independent of each, 

 other. Like many philofophers In this country, as well as elfewhere, they are difpofed to 

 think that the galvanic power depends upon the tranfition of oxigen ; but It may. be ob- 

 ferved, that there are many unequivocal fafts, which feem to prove that the common elec- 

 tricity alfo Is never excited,, but by the condenfation ordevelopement of the fame principle. 



Galvanic Flafh, 



Mr. Ciruickfiiank has favoured me with the remark, that a miftake appears In the uie of 

 the words zinc-face and filver face, at page 240 of our Journal for September, where an 

 account Is given of the luminous figns of galvanifm correfponding with the two eledlrici- 

 ties. I here relate the objeft'In his own words : the bi-ujh or jflajh always appears at the 

 " extremity of the -wire, luhich if immet-fed in ivater ivoiild difengage Mdrogen, or ivhat has been 

 " generally called the filver wire, luhereas the zinc, or oxigen -wire, exhibit only a faint luminous 

 ** point." And as he perfectly agrees in the remarks made at the page lad quoted, re- 

 fpedtlng the plus and minus eledtricities, he Is difpofed to fufpe£t,.that there may be fome 

 miftake In the original experiments, which were made to afcertain the ftate as to plus and; 

 minus of the extremities of the pile. I will repeat thofe experiments, in order that the 

 faCts may clear up this matter, and Ihew whether there be any ftriking difierence between 

 the galvanic and eledtric lights. 



