president's address — SECTION B 83 



•as it has that of iron, but at all events one may predict a great future 

 ior the new method. Wages and fuel are decreased to such an extent 

 that all copper smelters are bound, sooner or later, to avail themselves 

 ■of it." 



The^e is one practical point — of paramount importance in our 

 modern practice — which these early French references treat with scant 

 appreciation, and that is the possibility of fixing the termination of 

 the slag-forming period by means of a change in the color of the flame. 

 As remarked, the mattes used (which did not assay more than 33 per 

 ■cent, copper, and occasionally as low as 15 per cent., and even 10 per 

 •cent.) were very impure, and doubtless this fact greatly obscured the 

 ■color change. We have seen what special stress the Russian pioneers 

 of the process laid on this phenomenon, and how they interpreted it 

 as affording a positive means for determining the consummation of 

 the white metal stage of the blowing. The French accounts, on the 

 other hand, show that this most useful indicator was scarcely recognised, 

 and betray some confusion as to the meaning of the flame. This over- 

 sight, in fact, caused much unnecessary work, for it doubtless con- 

 tributed to the conservative belief that there was no other feasible 

 procedure than to divide the operation into two separate and distinct 

 ■campaigns, with an intermediate remelting of the white metal obtained 

 irom the first blow. The advantage of at once pouring this enriched 

 matte into a second vessel for completion, instead of cooling and re- 

 melting, was mc oted, and this may have been carried out ; but the still 

 :greater gain by simply smelting the matte beforehand to a somewhat 

 higher tenor (say, 50 per cent.) to begin with, and blowing this to white 

 metal by the flame, which has now become so easy a matter, and then 

 pouring and skimming the slag and finishing the white metal to copper, 

 was not recognised. 



By contrast, however, Manhes occupied himself with and patented 

 proposals for carrying the operation even beyond the ordinary finishing 

 point. He attempted (1880) the concentration of the precious metals 

 into a rich regulus, and also (1880-1) the refining of black copper direct 

 in the converter. As regards the former, the argentiferous copper 

 obtained was to be blown still further, imtil nearly all the copper was 

 oxidised, when the precious metals would be found in a small remaining 

 quantity of regulus. The other suggestion was to blow the matte to 

 Tilack copper, as usual, and then to refine and pole direct in the con- 

 verter under a charcoal cover. To facilitate these operations the 

 addition of 2 per cent, and more of spiegeleisen was deemed necessary, 

 and this was to be given dming the fusion of the matte (or the black 

 •copper) in the cupola furnace. These notions, however, led to no 

 permanent results. Generally, in ordinary work, manganese, silicon, 

 or phosphorus were to be used to furbish up the heat in mattes held 

 to be too low in sulphur, particularly towards the end of the convert- 

 ing- 



An interesting item, in view of the very recent application of the 

 pneumatic method to the refining of metals other than iron or copper, 

 is that even in these early days all manner of refuse metal, like pe\vter. 



