[ 399 ] 
Another very convenient and eafy method, of ex- 
hibiting the phenomena of the poiitive and negative 
electricity of the infide, and outfide furfaces, of a 
charged Leyden bottle, is by (lipping a cap of metal, 
furnished with a ball and wire, upon the outfide 
coating; and mounting it upon an eleCtric (land, 
in an horizontal pofition ; as tab. xiv. fig. .3.; 
or if the bottom of the glafs be turned much upward 
into the body of it, a piece of wood may be worked 
to its fhape, and cemented thereto.; and through the 
middle of this wood, a fhort tube of metal may be 
inferted, fo as to admit the wire which is con- 
nected with the ball to pafs through it; and be 
brought into contaCt with the coating of the jar, at 
pleafure '&h By this means, experiments may be 
made, at either end of the bottle with great facili- 
ty ; and other charged or exhausted, bottles ; ex- 
cited ribbons; or other electrics: the curved 
pointed wire, &c. 6c c. may be readily applied; and 
give, or receive a fpark; be attracted, or repelled ; 
according to the kind of eleCtricity in the two bo- 
dies, fo applied towards each other. By hanging 
a chain round either of the wires, and connecting 
it with one end of the difcharging rod; and bring- 
ing the other end of the rod, fo as to leave a pro- 
per fpace between that and the ball on the wire, at 
the oppolite end of the bottle ; the flame of a ta- 
per, &c. may be interpofed ; and (hew the direction 
of the eleCtricity in the difcharge : or a cork-ball, 
hung by Jilk, may play between them, in the man- 
ful For many experiments, it needs only to be conne&ed 
with the curved metal, or wood, in which the charged bottle is 
placed. 
3 
net v 
