414 Mr. A. Dick's Contributions to the Metallurgy of Copper. 



split at the edges when hammered out at a dull red heat after 

 having been melted under charcoal. They could, however, be 

 hammered out when cold without cracking in the least. The 

 pieces experimented on weighed about 150 or 200 grs.; possibly 

 larger pieces would be more difficult to hammer out without 

 cracking, but it would require an experienced coppersmith to 

 give an opinion on the working properties of such pieces. Similar 

 pieces as those alluded to cut from the ingot of copper made at 

 the Hafod Works, cracked even when hammered cold after being 

 melted in hydrogen or under charcoal. The amount of lead was 

 not determined in this ingot. No complete analyses of copper, 

 such as wire or sheet, were made ; and in those published with 

 which the writer is acquainted, no mention is made of oxygen 

 as a constituent : but, what is curious, in some, metals such as 

 potassium, calcium and magnesium are said to occur. This 

 seems to require further investigation. Russian copper coin 

 was found to contain oxygen, but it seems to be less essential to 

 the malleability of this variety of copper than to the English 

 copper ; because when the oxide in Russian copper is reduced by 

 melting under charcoal, the metal may be hammered out even 

 at a red heat without cracking much. This seems to show greater 

 purity, though it is not equal to electrotype copper. 



Several experiments were made with the view of finding some 

 method of melting tough pitch copper without either increasing 

 or diminishing the amount of suboxide present in it, which, if 

 practicable, would allow of its being melted without losing mal- 

 leability. The two substances employed were common salt and 

 chloride of calcium, the former not chemically pure chloride of 

 sodium, but commercial salt. The method pm-sued was to melt 

 the salt and drop the metal into it. It was found that electro- 

 type copper, melted in this way, could be afterwards hammered 

 out either cold or at a dull red heat without cracking at the 

 edges in the least ; but that ordinary copper wire, after having 

 been so melted, cracked when hammered at a dull red heat. 

 When working with known weights of copper wire, it was found 

 to undergo considerable loss of weight. Thus in one experi- 

 ment the wire B lost, by melting under common salt, 2*44 per 

 cent. ; in another it lost 2'05 per cent. ; and in another, at a 

 temperature just sufficient to melt it, it lost 1*35 percent. When 

 the salt in which the metal had been melted was afterwards dis- 

 solved in water, there was left an insoluble substance which was 

 found to contain copper and chlorine, but which was not further 

 examined. The loss of weight was much greater when chloride 

 of calcium was employed, amounting in one case to 7*17 per 

 cent. No similar experiments were made with weighed quan- 

 tities of electrotype copper. 



