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VIII. "On the Lead-Zinc and Bismuth-Zinc Alloys." By A. 

 MATTHIESSEN, F.R.S., and M. VON BOSE. Received August 

 28, 1861. 



The fact that lead and zinc, and bismuth and zinc do not alloy 

 together in every proportion is well known, but there have been, we 

 believe, no determinations made as to the extent in which these metals 

 alloy with each other. 



The following experiments were made to ascertain quantitatively 

 what amount of zinc will dissolve in lead and bismuth, and, on the 

 other hand, the amount of bismuth and lead in zinc. 



The metals* were fused in a Hessian crucible over a 4-Bunsen 

 burner, stirred with a tobacco-pipe stem for a quarter of an hour, and 

 then allowed to remain quiet for half an hour in a fused state : during 

 the whole time a jet of gas was directed on the surface of the melted 

 metals. They were after this cast in a porous cell, which had been 

 previously heated to redness in a large crucible filled with sand. It 

 was generally about two hours before the metals became solid : in 

 some cases the crucible was placed in a furnace with a low fire so as 

 to cool much slower, but the separation of the metals did not appear 

 to be more perfect than when cooled in the usual manner. When 

 cold the cell was broken, and the top of the alloy separated from the 

 lower part by a blow of the hammer. 



The weight of each casting was about 300 grms., its height about 

 100 millims., and its diameter about 25 millims. 



Lead- Zinc Alloys. 



The Zinc-end. About 1 2 grms. were taken from the middle of 

 the end, avoiding the outside. The greater part of the zinc was dis- 

 solved in dilute hydrochloric acid, the residue dissolved in nitric acid 

 and precipitated by sulphuretted hydrogen ; the washed sulphide 

 oxidized by fuming nitric acid, and the lead weighed as sulphate. 

 Or, instead of precipitating by sulphuretted hydrogen, the mixed 

 nitrates were precipitated by ammonia and carbonate of ammonia, 

 and the lead weighed as oxide. 



The Lead-end. 8 grms. were dissolved in nitric acid, precipitated 

 by sulphuretted hydrogen, the filtrate evaporated almost to dryness, 

 * Purified as described in the Phil. Trans. 1860, p. 177. 



