Cavallo's multiplier

[1] Its purpose was to multiply, or amplify, a small electric charge to a level where it was detectable by the insensitive electroscopes of the day.

His machine consisted of four metal plates supported on a wooden board by posts, of which three were insulating and one conducting.

[3] Cavallo termed his device a multiplier, though 'addition' was perhaps a more accurate description of its operation, as the charge on C was accumulated by successive additions.

[1] Wilson's machine, described by its inventor in Nicholson's Journal in August 1804,[4] was a development on this concept which simultaneously operated two Cavallo's multipliers by means of a pair of reciprocating levers.

[1] The charge would thus accumulate more rapidly than Cavallo's multiplier and the machine could generate high voltages in a short period of time.

Cavallo's multiplier, from an 1890 illustration. [ 1 ] From left to right, the metal disks are the insulated charge receiver A , the insulated charge transferrer B , the insulated charge accumulator C , and the earthed disk D . An earthing pin E makes contact with a wire F connected to B .