Gutta percha, its discovery, history, and manifold uses.

Date:
1851
Catalogue details

Licence: Public Domain Mark

Credit: Gutta percha, its discovery, history, and manifold uses. Source: Wellcome Collection.

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    that some pieces of Gutta Percha are better non-conductors than others. Professor Faraday attributes this fact to there being a little free moisture sometimes worked up with it, which of course, injures its insulating powers. It is advisable, there¬ fore, to employ pieces specially manufactured for electrical pur¬ poses. “ When heated before the fire, and kneaded by the fingers, it will insulate as well as shellac, and without its brit¬ tleness and liability to break.” This property is strikingly illustrated by a fact observed by Mr. Brunton, chemist to the Gutta Percha Company. “ By connecting one pole of a gal¬ vanic battery with the earth, and asking a spectator to touch a wire from the other pole, if the party wear Gutta Percha soles and heels' he will not receive any shock ; if leather soles or heels, the circuit will be completed, and the party show the usual symptoms of having been electrified. Mr. Statham very much astonishes visitors by taking, or refusing to take the shock at pleasure ; he contrives to do this by standing on his Gutta Percha soles one moment, and on his leather heels the next!” Gutta Percha would also excellently answer for the disc of a plate electrifying machine, or even the cylinder of the ordinary one, as it is a remarkably good excitant of electricity. Sparks may be produced in a dark room, and all the phenomena of attraction and repulsion shown, by simply rubbing a piece of the Gutta Percha tissue with a silk handkerchief. For insu¬ lating stools, handles of discharging rods, and even Leyden phials and battery cells, it answers exceedingly well. To the Electrotypist, Gutta Percha is of peculiar service. Mr. Mercer says :—“ For taking moulds of casts or medallions, he could not have a better thing; the impression it takes is so ex¬ ceedingly sharp, and being unaffected by acid or mineral salts, may remain any length of time in the battery without the least injury. And as a covering for the battery itself, I let a prac¬ tical electrotypist give his own opinion; it is Mr. Palmer, Electrotypist to the three National Art Unions. He says :— ‘ The advantages to me as an electrotypist, by the use of Gutta Percha, have been very great, by its protecting properties from acids. Before our troughs were lined with Gutta Percha, we c 2
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