Mr. J. Napier on Copper Smeltinf/. 349 



99-46 98-60 100-00 



The first analysis given is of a large piece of brick ground up, 

 and which may be taken as a sample of the mass ; but the quan- 

 tity of lime and clay is not sufficient to bind the whole silica, 

 were they intimately mixed ; but the silica being in pieces about 

 the size of an ordinary pea, the alumina and lime causing their 

 adhesion is in proper proportion to form clay^ and is very plastic. 

 If only a small portion of such bricks be taken for analysis^ 

 nearly pm-e silica may be obtained, as shown in the third column 

 of the above table. The matters composing these bricks are 

 obtained from a quarry in the neighbourhood of Neath. These 

 matters are crushed under a stone, the materials are then wetted 

 and the mould for the brick filled. As the plastic ingredients in 

 these bricks are mechanically mixed, not in chemical union with 

 the quartz, we believe that gromid or crushed quartz mixed with a 

 small portion of alumina and lime, as shown in the above analysis, 

 or good fire-clay, would serve the same purpose. Indeed in Chili 

 such has been tried with success, and it might be much more 

 extensively adopted. These bricks expand by heat more than 

 other fire-bricks ; but they do not contract to the same extent, 

 which is a valuable property in reference to maintaining a solid 

 and close lining. 



Some Dinnas brick from the roof of a refining furnace much 

 exposed to the escape of oxide of copper, and also to metallic 

 copper being spurted upon them during poling, and which was 

 consequently corroded and left spongy^ gave by analysis — 



Silica 72-2 



Oxide of copper . . 27-0 



Oxide of iron . . . '6 



'Ws 



Another quality of fire-brick sometimes used in the copper 

 works is from Pembroke. 



The following analysis of these is by Mr. John Cameron, of 

 Spitty Works, to whom wc are indebted for several analyses in 



these papers. sni^a 88-43 



Alumina .... 6-90 

 Oxide of iron . . 1-50 



Lime 3-40 



Magnesia .... trace 

 100-23 



