JOURNAL 



OF THE 



ASIATIC SOCIETY OF BENGAL, 



Part II.— NATURAL SCIENCE. 



No. II.— 1887, 



X. — On the Effects produced by Small Quantities of Bismuth on the Ductility 

 of Silver. — By Surgeon-Major J. Scully, Assay Master, Calcutta. 



[Eeceived June 13th ;— Eead July 6th, 1887.] 

 It is well known that alloys of silver and bismutli, in certain propor- 

 tions, are brittle. In Dr. Percy's valuable work on Metallurgy (Silver 

 and Gold — Part I), it is stated that alloys of silver with bismuth, in the 

 proportion of 50 per cent, and 33 per cent, of the latter metal, are brittle ; 

 while an ore of silver and bismuth, called Chilenite, in which bismuth 

 occurs only to the extent of 14"4 to 15'3 per cent., is said to be malleable. 

 The least amount of bismuth, however, which will injuriously aiffect the 

 ductility of silver, for example, in such an operation as the lamination of 

 silver bars for coinage, does not, so far as I am aware, appear to have 

 been experimentally investigated. It may here be mentioned at the 

 outset that an alloy of silver and bismuth may, by careful hammering, be 

 extended considerably, so as to pass muster as malleable ; although, if 

 subjected to lamination by means of steel rolls, the same alloy will 

 crack at the edges and thus show a deficient ductility, as compared 

 with pure silver or some silver-copper alloys. It is to the deficiency in 

 ductility, as tested by rolling, of silver containing only very small 

 proportions of bismuth that I here wish to call attention. 



My attention was first prominently directed, about two years ago, to 

 the injurious effects caused by small quantities of bismuth in silver by 

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