52 



and is then finely pulverized, when it is ready for use 

 by itself in the manufacture of dry pressed brick, which 

 burn to a beautiful red color. It is often mixed with other 

 clays, for example the calcareous clay A to form various 

 shades of buff to cream colored products. 



It is not advisable to go into any detailed description of 

 the process of brick-making, which is best seen at the brick 

 yard, but it may be briefly summarized as follows : — The 

 various sand-stock bricks, which get their name from being 

 made in sanded moulds ; the wire-cut brick, which are cut 

 off in the required sizes from a continuous column of clay 

 by passing a wire; and the hollow block, made in the same 

 way as the wire-cut brick, with variations in the die; are 

 all taken directly to tunnel dryers on steel cars, on which 

 they remain during the drying process. They emerge from 

 the opposite end of the tunnel, and are taken to down-draft 

 kilns. The dry-pressed bricks go directly from the presses 

 to the kiln, as they require no drying. These kilns are 

 single, or double, or continuous, and all burn by soft coal, 

 except the largest and latest one, which is an enormous con- 

 tinuous kiln, burned by producer gas. After seven to ten 

 days burning the kilns are cooled and the products are ready 

 for market. 



SWANSEA SEWER PIPE WORKS. 



The plant of the Dominion Sewer Pipe Co. is at Swan- 

 sea, to the west of Toronto. This company uses Medina 

 shale dug near Waterdown, thirty-five miles west of the city, 

 the shale being brought in cars to the plant at Swansea. Only 

 the upper weathered portion of these beds, from which the 

 lime and magnesia have been largely leached, is used in 

 the manufacture of sewer-pipe. The shale is ground as 

 at the Don Valley brick works, and is then mixed to a stiff 

 plastic putty with water. It is now forced by a plunger 

 machine through dies of the required size, turning out 

 thereby the hollow sewer-pipe, which are cut off by wires, 

 as in the case of the wire-cut brick. The pipes are then 

 slowly dried in large rooms with perforated floors, heated 

 very slowly but continuously with ordinary steam radiators. 



After thorough drying the tiles are removed to large 

 beehive down-draft kilns, where they are stood on end, the 

 smaller ones being nested inside the larger to conserve space 



