335 j 



XXXVII.— ON YOLATILIZATION OF ZINC FEOM GEEMAN- 

 SILYEE ALLOTS. Bx A. E. HASLAM. 



[Read, November 17, 1884.] 



Having read some time ago a Paper, in which it was stated by 

 the writer that in the manufacture of Grerman silver and brass con- 

 siderable loss is sustained by the zinc becoming vaporized during 

 the melting and cooling of the alloy, it occurred to me that the sub- 

 ject was deserving of further investigation, and accordingly the 

 following somewhat interesting experiments were undertaken by 

 me, first, to find the rate at which the zinc is vaporized by heat ; and 

 secondly, what action the other constituents, copper and nickel, exert 

 on this vaporization. Three specimens of commercial German silver 

 were obtained, having the following per centage composition : — 



The quantity used for experiment was in each case 2 -258 grammes, 

 and the following method was found both convenient and suitable 

 for estimating the loss of the zinc. 



The alloy was placed in a small porcelain crucible provided with 

 a close-fitting lid, through which passed two tubes, likewise of por- 

 celain, so that a current of dry hydrogen could be transmitted 

 through it, and over the alloy. The crucible and its contents were 

 then heated to bright redness in a Bunsen flame, and the alloy 

 weighed from time to time, to ascertain the loss consequent on the 

 evaporation of the zinc. The following table gives the results : — 



