Universal discharger

30 x 24 x 9.5
Wood, ivory, glass and brass

INDEX 1790 : P.IV.579

Exonerator, ut vocant, universalis, ex Henly inventione, quo variis in experimentis utimur ad dirigendam, - aliis corporibus communicandam magnam condensatae materiae electricae copiam.

Universal discharger, as it is called, after an invention by Henley, that we use in several experiments to conduct and, in other bodies, to communicate a large amount of condensed electrical material.

This device consists of an oblong base with a central column. The column ends in a horizontal dish, all in wood except for a central strip of the dish which is made from ivory. There are two glass insulating columns at the ends of the base supporting two horizontal brass rods. The rods can be moved nearer together or further apart, rotated and inclined. The central dish can be raised or lowered.

Connecting the rods to the positive and negative conductors of an electrostatic machine, and bringing their ends close together over the dish causes a spark. The ivory part of the dish is to prevent it from becaming burnt with continuing use of the instrument.

Carvalho, Rómulo de, História do Gabinete de Física da Universidade de Coimbra, Universidade de Coimbra, Biblioteca Geral, Coimbra, 1978, p. 684.

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