324? Mr. Musliet on the Fusion and Appearance 



Nevertheless, the inquiry as to the existence of local varia- 

 tions in the quantity of bromine, and as to the cause of such 

 variations, is one worth prosecuting ; and to those who are 

 favourably circumstanced for such investigations I may venture 

 to recommend the above indirect method of calculating the 

 relative proportions of two intermixed and similar ingredients, 

 which we owe to M. Gay-Lussac; and I do so with greater 

 confidence, now that I find its application to the case in ques- 

 tion sanctioned by the adoption of so experienced a chemist 

 as Dr. Ure. I remain. Gentlemen, yours, &c. 



Oxford, March 27, 1835. • Charles Daubeny. 



LIV. On the Fusion and Appearance of refined and unrefined 

 Copper, By David Mushet, Esq. 



To the Editors of the Philosophical Magazine and Journal, 



Gentlemen, 

 A S you thought my observations on the alloys of iron and 

 -^^ copper deserving of insertion in your Magazine (for Fe- 

 bruary last), perhaps you will allow me to forward you a few 

 extracts from experiments made some years ago, with a view 

 to ascertain what effect would be produced upon the strength 

 and malleability of copper by retaining to a certain extent 

 the alloy (chiefly tin) which is found in rough copper and 

 which it is the purpose of the copper-refinery to discharge. 

 In the first place, I obtained a quantity of shotted rough 

 copper, made from the furnace in which the copper, though 

 alloyed with other matters, first appears in its metallic form. 

 These shots were light and flaky, hard when struck, but at 

 the same time partially ductile. A quantity of pure shotted 

 copper made from the refinery, and having the form of flat- 

 tened spheroids and much denser than the other, was procured 

 at the same time for the purpose of these experiments. 



Exp, No. 1. A quantity of rough copper was fused in a 

 black-lead crucible with nearly an equal bulk of charcoal, and 

 poured into an open iron mould. The bar or ingot thus 

 made was fths of an inch thick, and when cold and broken, 

 was found to have crystallized in converging striae perpendi- 

 cular to the upper and lower surfaces, and declining towards 

 the outer edges of the bar. The grain was of a pale colour 

 inclining to gray, indicating the presence of tin. 



Exp. No. 2. Three bars procured in this way were melted 

 together in a black-lead crucible without charcoal, and poured 

 into a mould just at the moment when the melted copper put 



