ELECTRICITY. 327 



consists of two slips of leaf-gold A, suspended in 

 a glass B. The foot C may be made of wood or 

 metal : the cup D of metal. The cup is made flat 

 on the top, that objects to be electrified may be 

 conveniently placed upon it. The cup is about an 

 inch wider in diameter than the glass, and its rim 

 about three quarters of an inch broad, which hangs 

 parallel to the glass, to turn off the rain, and keep 

 it sufficiently insulated. Within this is another 

 circular rim, about half as broad as the other, 

 which is lined with silk or velvet, and fits close 

 upon the outside of the glass. Within this rim is 

 a tin tube, hanging from the centre of the cap, 

 somewhat longer than the depth of the inner rim. 

 In the tube a small peg is placed, and may be oc- 

 casionally taken out. To the peg, which is made 

 round at one end and flat at the other, the slips of 

 leaf-gold are fastened with paste, gum-water, or 

 varnish. These slips suspended by the peg, and 

 that in the tube fast to the centre of the cap, hang 

 in the middle of the glass, about three inches long, 

 and a quarter of an inch broad. On one side of 

 the cap there is a small hole to place wires in. It 

 is evident, that, without the glass, the leaf-gold 

 would be so agitated by the least motion of the 

 air, that it would be useless : and if the electricity 

 should be communicated to the surface of the 

 glass, it would interfere with the repulsion of the 

 leaf-gold ; therefore two long pieces, H H, of tin- 

 foil are fastened with varnish on opposite sides of 

 the internal surface of the glass, where the leaf- 

 gold may be expected to strike, and in connexion 

 with the foot. The upper end of the glass is 

 covered and lined with sealing-wax as low as the 

 outermost rim, to make its insulation more perfect. 



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