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.

    80/112 (page 74)
    appendix. ounce to six pounds. The glass, under this management is generally shivered into small pieces, and some of it is reduced into an impalpable powder. If it be so thick as to resist the force of the explosion, it is indelibly marked with the most lively prismatic colours. The weight laid upon the glass is always shaken by the ex- plosion, and sometimes thrown quite off' the ivory. To strike Metals into Glass, Stain Paper, fyc. . yake two sllPs of common window-glass, about three inches long, and half an inch wide ; put a small slip of gold, silver or brass leaf between them, and tie them together, or press them between the boards of a press, belonging to the universal discharger, leav- ing out a little of the metallic leaf between the glasses at each end ; then send a shock through this metallic leaf, and the force of the explosion will drive part of the metal into so close a contact with the glass, that it cannot be wiped off, or even affected by the’ menstrua, which otherwise would dissolve it. In this experiment the glasses are often shattered to pieces ; but whether they are broken or not, the tinge from the metal will be found in several places, and some- times through the whole length of both glasses. * If a chain which forms part of a circuit between the two sides of a charged jar, rest upon whitepaper, after the discharge has been made, the paper will be found stained with a blackish tinge at the juncture of the links. If the charge be considerable, the paper wil] be burnt through. If the chain repose upon glass, in- stead of paper, the glass will be stained, though only slightly. . J The electric fluid, while passing through a perfect conductor, is invisible ; but as the links of a chain are never in perfect contact, unless stretched to an extraor-