70 president's address — SECTION B. 



iron cupola, built in two parts — a fixed upper one, supported on 

 columns, and a lower one, detachable therefrom for repairs. Copper 

 matte was to be reduced in this apparatus by the pneumatic method, 

 by passing a blast through an accumulation of molten matte in the 

 lower portion, the upper level of which mass was to stand a little higher 

 than the tuyeres. The operation was as follows : — After heating the 

 furnace up with coke, a quantity of sand or other silicious material, 

 corresponding to the iron contained in the matte, and made into balls 

 with an admixture of tar, was first thrown on top of the coke bed. 

 The matte, broken into small pieces, was then fed in layers, alternating 

 with coke and quartz. The blast was gradually increased, and, as 

 soon as the matte-level rose above the tiiyeres, a violent action took 

 place, accompanied by the copious emission of fumes of sulphurous 

 acid. The method was claimed as adaptable to the treatment of 

 pyritous ores, and, though evidently nothing has come of the whole 

 proposal, it is an interesting anticipation of Hollway's ideas on the 

 blast-furnacing of pyrites, i.e., of modern pyritic smelting. 



Chemical Oxidation Processes, dc. — Following the above order of 

 development, we would now enter upon the true and actual initiation 

 of genuine pneumatic methods, in the sense of the rapid oxidation of 

 mattes, but, as a matter of convenience, let us speak of a few proposals 

 of a by-the-way character which sprang up about this time. The 

 most important of these was a scheme of accentuated oxidation with 

 the aid of other oxidising agents than the atmosphere, namely, solid 

 chemicals, which followed in the footsteps of similar proposals in the 

 iron industry, notably the processes of Hargreaves and of Heaton. 

 For a short time these chemical processes were, by some, accepted as 

 serious rivals of the Bessemer method itself, and though they certainly 

 would have been more justified in the treatment of copper than of 

 iron, they have not made more than a passing impression in either 

 metal. The earliest of these treatments for copper seems to be that 

 of Low,(A) who, in 1859, proposed to subject coarse metal (low-grade 

 matte) to the oxidising influence of currents of air in a reverberatory 

 furnace, adding to the molten bath predetermined quantities of a 

 mixture of peroxide of manganese, litharge, and saltpetre, the com- 

 position of this mixture to vary with the ores. The object was to 

 scorify and oxidise iron, sulphur, arsenic, &c., and to work up to metallic 

 copper. The process was said to decrease the duration of treatment 

 from 10 days to 36 hours, and to save correspondingly in fuel and labor. 

 Nothing further was done along this line, however, until 1870, when, 

 following one of Bessemer's patents, involving the addition of 

 saltpetre, and, under the stimulation of the flurry caused by the 

 chemical-puddling schemes mentioned above, Wagner {i) proposed 

 to adapt the notion to copper mattes. This idea (which in its original 

 conception really dates back to Patera, in 1855) was to fuse them 

 with 15 per cent, of equal parts of nitre and soda, oxidising the pro- 

 tosulphide of iron into oxide, and, by cautious application of the chemical 



(h) Journal des Mines, 1859, No. 28. 

 (i) Berg-u. Hiittenmann. Zeitg, 1870, vol. XXIX., p. 133 et seq. 



