348 



Mr. J. Napier on Copper Smelting. 



lowing table from Berthier of the composition of crucibles and 

 pots known to stand well in working, will serve as data for com- 

 paring with the bricks and bottoms of the copper furnaces. 



We may here remark generally, that the bricks which contain 

 the most silica stand the action both of fire and melting matters 

 best. 



Flintshire brick. — This sort is much used in the construction 

 of furnaces and chimneys in the copper-works of Wales ; they 

 are not used for lining the furnaces where the melted matters 

 are to come into contact with them, but in parts exposed to great 

 heat and air-currents. Their analysis gave — 



Silica . . . 

 Alumina . . 

 Protoxide of iron 

 Lime 



99-9 



These bricks are of a blackish-red colour and veiy hard. 



Fire-bricks from Lysnevnjdd, South Wales. — Used in large 

 quantity in the copper-works, both for fire-places and hearths. 



99-3 



Dinnus bricks, sometimes termed stone bricks. — These may be 

 considered indispensable in the process of copper smelting. They 

 are used where melted copper has to come into contact with the 

 furnace, biit are very soon corroded when exposed to the influ- 

 ence of oxide of copper. They are a coarse-grained brick, resem- 

 bling in appearance a conglomeration of small pieces of quartz 

 rather than an artificial brick. Their composition is — 



