814 ANNUAL REGISTER, 1804. 



■wliere it is s?t on fire in dilTerent 

 places, to undergo the process of 

 roasting : for as the ore, in its natu- 

 ral state, contains a great qu;intity 

 of sulphurj it is necessary that this 

 should be separated (which can only 

 be done by means of iire), before it 

 is fluxed into copper. The sulphur 

 goes ofi" in the form of vapour, and 

 is conveyed by means of a thie, con- 

 Be6ted with the kiln, to the sulphur 

 chamber, a place bnilt to receive it, 

 •where it sublimes, and becomes the 

 Mower of sulphur of the shops. It 

 is afterwards taken from hence, 

 melted in large copper puns, and 

 cast in moulds for sale. After the 

 ore has been thus roasted, which is 

 rather a tedious operation, occupy- 

 ing from three to ten months, ac- 

 cording to the quantity in the fur- 

 naces (which is generally from three 

 hundred to a thousand tons), it is 

 taken to the slacking pits, places 

 construcled of stone, about six 

 yards long, five wide, and two deep, 

 to be washed, and made merchant- 

 able. The poorest of this, that is, 

 such as contains from li to 2 per 

 cent, of metal, is then conveyed to 

 thesmelting-houses atAImwch port: 

 the rest is sent to the company's 

 furnaces at Swansea and Ivaven- 

 head. By the processes of roast- 

 ing and washing, the ore is much 

 reduced in quantit^^; it is consider- 

 ably improved in quality: and the 

 ivater is so richly impregnated with 

 cbpper, which is dissolved by the 

 acid quality of the sulphur, that, by 

 means of old iron immersed in it, 

 according to the German method, it 

 produces such quantities of fine 

 copper, that the proprietors have 

 obtained in one year, upwards of a 

 hundred tons of the copper precipi- 

 tated from the water. Their ave- 



rage export of precipitate is sixty 

 tons per annum. 



The proprietors also turn the 

 water drawn from the beds of cop- 

 per, which is highly impregnated, 

 through reftangular pits, similar to 

 those used in the above process. 

 These are each about thirty feetlong, 

 twelve bi'oad, and two deep. Any 

 kind of iron, either old or new, is 

 used, but in general, for the sake of 

 convenience, they procure small 

 plates of cast iron. The iron be- 

 comes dissolved by the acid, and is 

 suspended in the water, whilst the 

 copper is precipitated. Care is 

 taken to turn the iron every day, 

 in order to shake off the incrusta- 

 tion of copper formed upon it, and 

 this is continued till the iron is pcr- 

 feftly dissolved. The workmen 

 then drain off the water, and rake 

 together the ore in the form of mud, 

 which, when it is become, by dry- 

 ing, of the consistency of a softish 

 paste, they bake in ovens construct- 

 ed for the purpose. After this pro- 

 cess it U exported with the other 

 ore, to Ravenhead or Swansea. One 

 ton of iron thus immersed, produces 

 near two tons of copper mud, each 

 of which, when melted, will yield 

 sixteen hundred weight of copper; 

 and this sells at a considerably higher 

 price than* the copper which is ilux- 

 ed from the ore. An attempt .was 

 made not long ago by JMons. V ally, 

 of Holywell, to precipitate the cop- 

 per by means of lime ; and another 

 by some gentlemen from London, 

 to do the same by tin, but both the 

 experiments were unsuccessful. 



This method of obtaining copper 

 by means of iron, has long been 

 adopted in Germany, but has only 

 been known in this country a few 

 years j and its first discovery was 



owing 



