Lectures on electricity / by James Ferguson, F.R.S.

  • James Ferguson
Date:
1825
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on electricity / by James Ferguson, F.R.S. Source: Wellcome Collection.

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    ] 4 19. X is a thin brass plate, to be hung- to the prime conductor by a metal hook; and Y is another of the same sort, but a little larger, to be placed below it. A brass wire is fixed into the middle of the plate Y} and is moveable up or down in a brass socket Z, for raising or letting down the plate, which may be fixed at any proper height by means of the screw z ; and the lowest end of the socket may either be stuck into a hole in the wooden foot M of the prime conductor, or have a metal stand of its own, which is the most usual way. For, in making experiments with it is, no matter under what part of the conductor it be placed, if the other plate be hung directly over it. 20. b is a large plumy feather, such as young ladies wear in their caps. That of an ostrich is the best. 21. m is a small lock of cotton, part of which must be drawn out into a short thread, and thereby fixed with a bit of bees-wax to any part of the undermost side of the prime conductor, (any where between Q and X would be better than where it is represented) and then, before the experiment with it be made, it should be pulled out by the hands into such a lax state, as that the different parts of it may only hang together by small shreds, and the lowest part of it should be drawn out to a shred. 22. In Fig. 6, A B C is a bended wire, the end A being made blunt, and of such a size as to fit either of the round holes in the prime conductor, instead of either the straight wire N, or the crooked wire c d; and the end c must be a sharp point. 23. In Fig. 2, A is a glass jar, coated on the outside, and lined on the inside with tinfoil to about two inches short of its top, which is stopped with a thin cork, first dipt all over in melted wax.8 A straight brass wire is put down through the middle of the cork, quite to the Note 8. A top, turned from dry mahogany, is better adapted to the purpose, as carbonised corlc is a conductor of electricity.
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