A manual on dental metallurgy / by Ernest A. Smith.

  • Smith, Ernest A. (Ernest Alfred)
Date:
1903
Catalogue details

Licence: In copyright

Credit: A manual on dental metallurgy / by Ernest A. Smith. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    234/334 (page 214)
    Properties.—Tin is one of the whitest metals, but possesses a peculiar faint yellow tinge ; it rivals silver in ]ustre and its surface is capable of taking a fine polish. It undergoes little change in dry or moist air at ordinary temperatures, but it tarnishes slowly in the presence of sulphuretted hydrogen owing to the forma- tion of a film of sulphide. If heated in air it rapidly oxidises to stannic oxide (SnO.,), which forms the well-known polishing putty powder, but the i^ure metal, if melted at a low temperature and poured out, retains its resplendent lustre for a considerable time. Tin has a characteristic odour which becomes evident when the metal is warmed by being held in the hand for a short time. It is a little harder than lead but softer than gold. Water has no action on the metal, but it is readily soluble in hot hydrochloric acid ; boiling concentrated sulphuric acid acts violently on the metal, while the action of the dilute acid is less energetic. Dilute nitric acid acts violently upon it, liberating nitrous fumes, and converting the tin into metastannic acid, which settles at the bottom of the vessel as a white powder. Tin is also soluble in alkaline solutions. A bar of tin when bent emits a peculiar crackling sound, known as the cry of tin, caused by the friction of the crystalline particles. Tin is one of the least tenacious of the metals, only lead, antimony and bismuth being inferior to it in this respect; it is, however, very malle- able and can be easily rolled out to thin foil of less than yyVsyth of an inch in thickness. Tin may be welded by the application of pressure, when two clean surfaces are brought into contact. It |iossessPS little ductility, but with care may be drawn into wire. At a