[22] By taking a spark from the wire, the electricity within the bottle is diminished; the outside of the bottle then draws some from the person holding it, and leaves him in the negative state. Then when his hand or face is touched, an equal quantity is restored to him from the person touching.
[23] Our tubes are made here of green glass, 27 or 30 inches long, as big as can be grasped.
[24] This simple easily-made machine was a contrivance of Mr. Syng's.
TO PETER COLLINSON, ESQ. F. R. S. LONDON.
[Observations on the Leyden Bottle, with Experiments proving the different electrical State of its different Surfaces.]
Philadelphia, Sept. 1, 1747.
Sir,
The necessary trouble of copying long letters, which, perhaps, when they come to your hands, may contain nothing new, or worth your reading, (so quick is the progress made with you in electricity) half discourages me from writing any more on that subject. Yet I cannot forbear adding a few observations on M. Muschenbroek's wonderful bottle.
1. The non-electric contained in the bottle differs, when electrised, from a non-electric electrised out of the bottle, in this: that the electrical fire of the latter is accumulated on its surface, and forms an electrical atmosphere round it of considerable extent; but the electrical fire is crowded into the substance of the former, the glass confining it[25].