312 TINNING, PLATING, &C. 



only in England, but in France* Holland, Sweden, &c. though 

 from the cheapness of our tin, and the excellency of some sorts 

 of our iron, the greatest share of the tin plate trade must ever 

 center with ourselves. Our coal is another circumstance which 

 tends to give Great Britain an advantage over some other coun. 

 hi' s, in such manufactures as require a great consumption of fuel. 

 Wood was scarce in Saxony about a century ago, and it is now 

 still more scarce in France. They are beginning, it is said, in 

 that country, to use coal and coak, or chirnd j it. coal, called 

 by them charbon de terre epur6, and they have grunted a patent 

 to an individual for the preparation of it*. Another individual 

 has begun to distil tar from pit-coal, and he gets about five pounds 

 weight of tar from an hundred of coal (which is pretty nearly 

 what I suggested, in 1781, as possible to be obtained from the 

 same quantity, Vol. II. p. 352). The French + expect great ad- 

 vantage from this mode of depurating coal : but we have nothing 

 to apprehend on that score ; for the patriotic zeal of the Earl of 

 Dundonald has put us in possession of every advantage which can 

 be expected from, a discovery, which he has had the honour of 

 bringing to perfection. 



The plating of copper is performed in the following manner: 

 Upon small ingots of copper they bind plates of silver with iron 

 wire, generally allowing one ounce of silver to twelve ounces of 

 copper. The surface of the plate of silver is not quite so large as 

 that of the copper ingot ; upon the edges of the copper, which are 

 not covered by the silver, they put a little borax ; and exposing 

 the whole to a strong heat, the borax melts, and in melting contri. 

 butes to melt that part of the silver to which it is contiguous, and 

 to attach it in that melted state to the copper. The ingot, with it's 

 silver plate, is then rolled under steel rollers, moved by a water 

 wheel, till it is of a certain thickness ; it is afterwards further 



* Acad des Scicn. a Paris, 1781 ; where M. Lavoisier gives an useful me- 

 moir on the comparative excellencies of pit-coal, coak, wood, and charcoal, as 

 fuels. II suit de ces experiences, que pour produire des effets egaux, il faut 

 employer : charbon de terre 660 livret ; charbon de terre charbonne 552 ; 

 rharbnn de boi me!6 960 ; bois de hfilrff 1 125 ; bois de cliene 1089. 



t II suffit dc dire qu'clle peut fournir A la capitale un nouveau cliauflage, de- 

 vcnu n6cessuire dans un moment ou 1'on est monact d'une disette de bois; 

 qu'elle pent oiivrir dans le royaume une nouvelle brancc de commerce ; etablir 

 de noDvelles manufactures; faire valoir des mines, restccs jusqu'a present inn- 

 tiles. L'Esprit des Journ. Jmllet, 1785. 



