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CHAPTER XI.

Containing an examination of the principal, or chief property, ‘whicheleStricians have ascribed to electric atmospheres, and which theyhave applied to explain the phcenomena produced from SeignorVolta's Rleclrophorus.

PTr^HE electrophorus, ar perpetual electric machine, the in-JL vention of Seignor Volta, the Italian philosopher of Co-ma, may be made with any sulphureous, or resinous electric, andwill answer very well without the addition of a glass plate.Take about two pounds of sulphur, melt it, and pour it intoa circular mould, or a deep plate, with a smooth bottom, whichhas been previously rubbed slightly over with sweet oil, andwiped off again, that it may not either injure the surface of thesulphur, by softening it, nor by letting it stick to the mould.Provide a metal cover, or a board covered over with tin-foil, ofnearly the same size of the sulphur-cake, and let it be furnishedwith a glass handle to six into a socket, or to screw into thecenter of the cover (see plate II. fig. 6.) This simple machineis worked by first exciting the sulphur, or rubbing it with apiece of flannel, or woollen cloth, and placing it upon a tablewith the excited part uppermost.

The metal plate is then to be taken by the glass handle, andplaced upon the excited cake, and touched with your singer, orany conducting body. On touching the cover, while standingupon the sulphur, it will either give or receive a spark. If the

metal