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.

    84/112 (page 78)
    APPENDIX. through the same hole, of one thirty-eighth of an inch in diameter, and observed how many inches of each could be melted by the explosion of his battery, which contained 225 feet of coated surface : taking care, in all these experiments, to charge it to the same degree, as ascertained by his electrometer. The results were as follow : Indies. Of Lead the discharge melted 120 ; the same metal melts by fire at 612°Fah. Tin 120 442° . Iron 5 . . 21637° . Gold 3£ . 5237° . Silver Copper . Brass . not quite Oj . . do. . . do. • . 4717° . . 4587° . .. 3807° . The Electrical Earthquake. Van Marum, with the battery above mentioned, in order to imitate the phenomena of earthquakes, followed Dr. Priestley’s method of making the electrical explosion pass over a board, floating on water, on which several columns of wood were erected ; but this succeeded only once. Reflecting that the electric explosion exerts the greatest lateral force when it passes through imperfect conductors, and that water is probably its principal subterranean conductor, he laid two smooth boards upon each other, moistening with water the sides which were in contact: upon the uppermost he placed pieces of wood in imitation of buildings, the bases of which were three inches long, and Is broad. When the charge of the battery was transmitted between the boards, all these were thrown down by the tremulous and undulatory motion of the board on which they stood