A treatise on electricity wherein its various phoenomena are accounted for, and the cause of the attraction and gravitation of solids, assigned : To which is added, a short account, how the electrical effluvia act upon the animal frame, and in what disorders the same may probably be applied with success, and in what not / By Francis Penrose.
- Penrose, Francis, 1718-1798.
- Date:
- 1752
Licence: Public Domain Mark
Credit: A treatise on electricity wherein its various phoenomena are accounted for, and the cause of the attraction and gravitation of solids, assigned : To which is added, a short account, how the electrical effluvia act upon the animal frame, and in what disorders the same may probably be applied with success, and in what not / By Francis Penrose. Source: Wellcome Collection.
17/40 (page 17)
![[ *7 ] haufted receiver, the a&ion of the mercury on that fubtil fluid gives the mercury the appear¬ ance of fire ^ but obferves, that in all thefe ex¬ periments on mercury, no light is to be obtained without motion, and that the fame motion which produced this light in vacuo, did not produce it, when given to mercurial globules in open air. This experiment fhews us, that there was a lar¬ ger quantity of light in the exhaufted receiver than when it was filled with common air; nay farther, that the fubtil fluid contained in the ex¬ haufted receiver, was light; but, for want of mo¬ tion, was not perceptible by our fenfes; but by fo fmall a motion as that of the defcending mer¬ cury, it was puflied forward in the fame man¬ ner, as light from a candle, or other luminous bodies. We alfo find, that the fame experiments performed in an unexhaufled receiver, would not produce the phenomenon of light • which one might eafily fuppofe to be the cafe. For in the exhaufled receiver, any the leaft motion, that is fufficient to pujh this fubtil fluid (light) from one place to another muft give us the perception of light; but in the unexhaufled receiver the motion or friSlion muft be great enough, not only to pujh the air from place to place, but alfo to break it fo fmall, as to be in form of light v which he fhews us by his third, fourth, and fifth experi- C ments](https://iiif.wellcomecollection.org/image/b30375186_0017.jp2/full/800%2C/0/default.jpg)
