328 The Philosophical Society of Glasgow. 



channel leading to another hole being the receptacle. Many of these 

 rude furnaces have been discovered in Cornwall, in which have been 

 found charcoal, slags, and even the reduced metal. It is just possible 

 that copper was reduced in Britain by the same simple means ; for in 

 many of the northern districts carbonate and oxide ores of copper exist 

 at this date. A great deal might be written on this very interesting 

 subject ; but so much has been ably done by others, that it may be only 

 necessary to name authonties for those requiring a deeper knowledge 

 than can be attempted in a paper of this limit. Mr. Napier, in his 

 recent work on the Anciott Workers in Metals; Messrs. Philips and 

 Darlington, in their Records of Metallurgy; and Messrs. Hunt and 

 Mitchell, in a series of papers published in the Mining Journal of 

 1848, 1849, and 1850, give much and valuable information. It will 

 not be necessary to trace copper smelting in this country further back 

 than 1823, when Mr. Vivian described the process then in use as an 

 illustration of the best mode ; and although there is much of historical 

 interest in mining statistics, showing the working of the trade from 

 the twelfth century, the process of reduction, so far as ascertained, did 

 not much differ. In fact, no very definite information was ever pub- 

 lished regarding the process till Mr. Vivian's communication in the 

 Twenty-first Volume of the Annals of Philosophy. The copper trade 

 has always, in this country, been a monopoly, 4Hid the process of smelt- 

 ing, till described by him, a secret. 



Mr. Vivian thus describes the process of smelting, which I give in a 

 condensed form, as it is of importance to institute a comparison of what 

 was known at that date, and the state of the art at the present time. 



The copper ores, being conveyed from Cornwall and Devonshire to 

 Swansea on account of the coal products in that district, are fii*st placed 

 in calcining furnaces, eleven or twelve feet long and fourteen to sixteen 

 feet wide, of a hexagonal form, to undergo the first process, calcination, 

 the charge being about three and a-half tons. This continues for twelve 

 hours, and during that period both sulphur and arsenic are got rid of — 

 the former in the state of both sulphurous and sulphuric acid. The 

 copper and iron are both oxidized. 



The second process is to place the calcined ore in fm-naces eleven and 

 a-half feet long by seven and a-half feet wide, the object being to melt 

 the charge. When fusion takes place, the mass is well rabbled, to 

 allow the metallic sulphuret to subside, and when the slag, or earthy 

 matter, becomes liquid, it is skimmed off, and fresh charges of ore 

 added, till the furnace can contain no more, and it begins to flow out at 

 the door. 



The furnace is now opened at the tapping-hole, and the product 



I 



