178 EXPERIMENTS ON THE ELECTRIC PILE. 



which was fixed to the end of the conducting wire j at other 

 times by the lefs pointed end of the conducting wire itfelf. 

 Beautiful phe- When the furface of the quickfilver was touched with the 

 du«d n by P the end of a ilen der wire inftead of the needle, a very finking 

 combuftion of phenomenon enfued : the combuftion of the extremity of this 

 af the wire. w j re was e ff ec ^ ec j ^vith fuch force, that it threw out fparks on 

 all fides, which formed thoufands of apparent rays, reprefent- 

 ing beautiful funs fome inches in diameter. By gently lower- 

 ing the end of the wire in proportion as it was difperfed by the 

 combuftion, this appearance could be continued at will. It 

 is feen in fome degree likewife when the quickfilver is touched 

 with the point of a fine needle ; but then it is of (hort dura- 

 tion, as it ceafes as foon as the needle has left its point. The 

 experiment was repeated with wires of ^|^, ~ T , and —tj. of 

 an inch in diameter : that of the middle iize gave the largefl 

 and molt brilliant funs, but the fmaller fucceeds better when 

 the power of the pile is lefs. 

 Quickfilver oxi- On taking wires too thick to be melted, the oxidation of 

 faceT 'the"*" ^ quickfilver at »t* furface by each fpark was more diftin&ly 

 fparks. feen, fpots of upward of a line in diameter being formed. 



Platina fufed by The extremity of a wire of platina, about ^j of an inch in 

 the pile. diameter, was melted, and formed a globule* 



Sparks upward of The fparks ifliiing from the end of the communicating wire, 

 a line in diame- w hen it was not too.flender, were more than one-tenth of an 



inch in diameter. 

 Piles of an equal ^ n comparing the intenfity of the electricity of this pile 

 number of pairs, with that of the former of zinc and filver an inch and a half in 

 diameters 1 , give diameter, both by the fimple contact of the Doctor's moll 

 equal intenfities, fenfible electrometer, and by the condenfer and an elecfrome- 

 fto d ck mH not- ter of lefs fenfibility, they were found precifely the fame, 

 withftanding when the fame number of pairs were ufed : they charged the 



they differ fo battery before defcribed to the fame height : the fhocks given 

 much in fuhng . . •* , , . . . , , .. • /• t t 



metals. D y the battery thus charged were m both cales precitely the 



fame : and in thofe from the piles the difference was fcarcely 



perceptible. 



Attempt to ac- It appears ftrange, that two piles fa equal as to intenfity, 



count for this. an( j charging large batteries in fuch an equal degree, fhould 



produce fuch different effects in fufing metals. To form a 



juft notion of this, obferves Dr. Van Marum, we muft diftin- 



guifli the action of a pile which is infulated from that of one 



which is not. In th<; latter there is a ftream palling continually 



from 



