ALLOYS OF COPPER. - Copper unites with facility with almost all other metals, and a large number of its compounds are of the highest importance in the arts. Indeed copper is much more important and valuable as a constituent element in numerous alloys than it is as pure metal. The principal alloys in which it forms a leading ingredient are - lst, brass ; 2d, bronze ; and 3d, German or nickel silver ; and under these several heads their respective applications and qualities will be found. These alloys are each much diversified as regards the relative proportions of the various metals which enter into their constitution, and these differences similarly modify the appearance and physical properties of the compounds. In this way for practical purposes they may be regarded as a great number of separate metals, each possessed of distinct qualities which fit it for special industrial uses. The following tables, compiled from various authorities, represent the analysis of typical examples of the several alloys: - TABLE A. - Composition of Brass or Copper and Zinc Alloys.

Aluminium bronzes are composed of pure copper with from 2i up to 10 per cent, of aluminium. Phosphor bronze, according to the purposes for which it is intended, contains from 3 to 15 per cent. of tin and from 1 to 2i per cent. of phosphorus. Small proportions of other metals, among which are silver, nickel, cobalt, antimony, and bismuth, with sulphur, frequently enter into the composition of bronzes.