IMPROVEMENTS IN GALVANISM. 3_ 



fentils of glafs, fo as to render the reparation very fmall. I therj 



arranged feveral feries of plates of one inch, to plates of feven 



inches in diameter; becaufe he has not particularized the fize of 



the plates he employed. I arranged piles of thefe different lizes 



to the number of twenty pairs in each arrangement, and 



obferved not the flightefl galvanic effeft, either by my tongue 



or by any other tcft. 1 employed a very excellent condenfer; The experiment 



no influence at all was evinced ; and, laftly, I fubjeded it to '^''^ "°^ f"«eed. 



the moft delicate eledrofcope we have, viz. the mufcular 



fibres of a frog. Not the flighteft difturbance took place, 



although I fancy I have demonftrated, in the elements of gal- 



vanifm I have publifhed, that the fenfibility of this animal 



eledrofcope is fifty thoufand times greater than that of the 



condenfer. 



As to the charging of a Leyden phial, I am convinced it is Convlftlon of 



perfe6tly erroneous to fuppofe it has ever been done. I have , ^".'L^°'' ^^^'^ 

 ' ■' ' ' . galvaniim cannot 



employed from fifty pair of plates to fifteen hundred, and never charge a Leyden 



yet have produced any charge. Nor indeed could fuch beJ^'"' 



expe6led from the weak intenfity of the ftate of electricity in 



galvanic operations ; for a jar cannot be charged until a 



fufficient quantum is accumulated to overcome the refifiauce 



of the furrounding air, fo abfolutely requifite to the charging 



of a Leyden phial. 



I am, Sir, 



Your's, &c. 



C. WILKINSON. 



ANNOTATION. W. N. 

 THE valuable obfervations in the preceding letter, will Form of gal- 

 naturally fuggeft improvements to thofe who are employed in ^a"'^ apparatus 

 the conitruction or galvanic apparatus. It mull be a great 

 advantage, that the expence of copper and the work of 

 foldering, or placing it, will be almoft entirely faved. Fig. 1. 

 Plate III. (hews a fimple method of difpofing a fingle plate of 

 zinc of large furface in a trough. It is fuppofed to have been 

 made fufficiently hot to bed itfelf in cement at the bottom of 

 the box in which it is placed, and its two ends A and B are 

 fecured in the fame way. The fliaded fpaces reprefent the 

 cavity occupied by acid, and the dotted fpace is left empty. 

 B 2 A com- 



