240 Scientific Netvs, Accounts of Books, (sfc, 



which the furfaces of the filver plates are oppofed, a flafli or bruflv of light, vifible in clear 

 fun (hine, is feen upon tlie furface of the water at the moment of conta£t or immerGonj 

 attended with a noife exa£lly fimilar to that of plunging a red hot wire in water, and ac- 

 companied with an ebullition of the fame kind, as is produced by fuch an immerfion. The 

 length of the brufti is about half an inch, and the noife may be heard acrofs a room. On 

 the contrary, if the permanent connexion, or immerfed end of the wire be at the filver 

 end, or that extremity which would feparate hidrogen from water, and the application 

 or contaft be made to the fluid at the zinc or oxigen end, nothing is feen but a 

 fmall globular fpeck of light, fcarcely vifible unlefs flie machine be very powerful at 

 the fame time that there is very little effervefcence, and no noife at all. 



From my experiments at page 184 of the 4th Volume of this Journal, which 



have fincc been repeated and varied by numberlcfs operators, it is determined that 



the zinc or oxigen fide imparts the plus ftate of eleftricity, and the other fide the 



minus. The point of the wire was therefore plus when it gave out the luminous 



brufh, and minus when the fluid was filently condudted. This property of the two 



eledlricities was long ago fhewn by Franklin, and from feme new fa£ts refpefling the 



operation of low points, was applied by myfelf to the conftruftion of an inftrument 



called the Diftinguiflier of Ele£tricity, of which a drawing was publiftied in my Intro- 



du£lion to Natural Philofophy about fourteen years ago. The courfe of elcflricity from 



a battery, that is to fay, of a large guantity at a low or moderate intenfity, along the 



furface of fluids or moid fubftances, was the obje£l: of a feries of experiments many years 



ago by Dr. Priellley, which he has publilhed in his Hiftory of Eleftricity. Dr. Wollafton 



has communicated fome very effe£tive experiments to the Royal Society, by which the 



identity of the eledrical and galvanic powers appears to be placed beyond controverfy, an 



account of which will foon be laid before the reader. 



