Essays and observations on the construction and graduation of thermometers, and on the heating and cooling of bodies / By George Martine, M.D.

  • George Martine
Date:
1787
Catalogue details

Licence: Public Domain Mark

Credit: Essays and observations on the construction and graduation of thermometers, and on the heating and cooling of bodies / By George Martine, M.D. Source: Wellcome Collection.

    176/192 (page 166)
    / i66 The VARIOUS DEGREES What ftill vaftlyincreafes the fufiblenefs of thefe metals is the addition of bifniuth or tin-glafs, a marcafite or fulphureo-metallic fubftance, not fo eafily melted as tin. That bifmuth Sir Ifaac New- ton ufed in thefe curious experiments, we fhall juft now have occafion to copy from him, did not melt with a heat under 460*. And Dr. Muffchen- broelc’s bifmuth was much harder to diflblve, to wit, at^r. 1051 f. And a golden marcafite, though more fluxil, took gr. ^06 to melt it. A mixture of tin and tin-glvifs melts at a heat lefs than what is requifitc to melt either feparatelyj:. When they were in equal quantities, the compound melted at gr. 283 I|. If you alter this proportion, the mixture becomes fufceptible of a greater heat. When the tin was double the bifmuth, it did not melt with a heat under gr. 334§. And it ftiffened in this heat when the tin was to the bifmuth as 5 to 3 **. And if the proportion of bifmuth be very fr.'.cll, the heat required to keep the compound- in fufion is ftill greater, and comes nearer to that of melting tin. When there was eight times morct * Phil. Tranf. Abr. IV. 2. p, 2. f Muflehenbr. Ibid. t Ibid. 1] Newton, Ibid. p. a. i Ibid. Ibid. tin f