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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    for, on applying the discharger B, there was no flash. And always, on stripping off the coating from such a jar, I have found the glass to be cracked or rent. So that, all the electric virtue, which the inside had received from the machine, ran through the crack to the outside, and was carried off by the coating and table. This, I think, shews very plainly, that the electric virtue can- not pass through sound glass, unless it comes with a force sufficient to break it, as lightning often breaks glass windows EXPERIMENT XXVI. Shewing, that in Charging a Jar, as much Fire is carried off from its outside by the coating, as is thrown into its inside by the lining. 67. Put a crooked wire, as d e (Fig. 3, of Plate I.) into a hole in the top of the ball D, which is fixed on the top of the bended wire B (See § 24,) the point e of the wire d e being made sharp, and of equal height with the top of the great wheel A of the mill (Fig. 4, of Plate II.) which, in the 15th experiment, was turned by a stream of electric fire, from the point C of the crooked wire (Fig. 6, of Plate I.) when the blunt end A was stuck into a hole in the prime conductor. Things being thus prepared, set the jar A (Fig. 3, of Plate I.) upon a large pane of glass, dry and free from dust; which will cut off all electric communication between the jar and the table. And let the jar and mill be so placed, that the ball C of the jar-wire may be within the eighth part of an inch of the prime conductor, and the wings of the great wheel of the mill about an inch from the point e of the additional bended wire d e. Then, turn the glass globe of the electrical machine by the winch, to charge the inside of the jar; and the electric fire from the outside will go off from the coating, by the wire B D d e, and turn the mill the same way, and with the