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.

    22/112 (page 18)
    back of the frame all round, except the top part, and form a communication between that gilding and the gilding behind the glass ; then put in the board, and that side is finished. Turn up the glass, and gild the foreside exactly over the back-gilding, and when it is dry, cover it, by pasting on the panned of the picture that had been cut out, observing to bring the corres- pondent parts of the border and picture together, by which the picture will appear of a piece, as at first, only part is behind the glass, and part before.'’ 28. The stool on which people are electrified, is a mahogany board, supported by four pillars of solid glass, each about half a foot long ; but if they were eight inches in length, it would be so much the better. The edges and corners of the board ought to be well rounded off, and nothing about it left rough or sharp. Those who apply electricity for medical purposes, ought to have a chair, with glass feet, eight inches long, for patients to sit in, who cannot stand on a stool. 29. I shall now describe the figures on Plate II. which are representations of some models of machines that I have lately made ; and, for the amusement of those who attend my lectures, I set these moddlesin motion by a stream of electric fire.11 It must be confessed, they do not properly belong to the class of electrical experi- ments, because they might be put into motion by water, wind, or weights. Yet, as it is not unpleasing to see them move by electricity, perhaps some gentlemen who have a mechanical turn, and are provided with electrical machines, may like to copy these moddles, both for their own amusement and that of their friends.—All the wheels and trundle-heads are made of card-paper. Note 11. Instead of the ° stream of electrical fire,” producing this motion we may more philosophically ascribe it to the current of electrified air, which possessing a similar electricity with the point, is repelled by it, and striking against the vanes, impels them round.