Tools and Conveniences of the Year. 



189 



deep, and may be from ten to thirty feet long, according to the 

 spa^ce required. In the middle of the box is a partition, ex- 

 tending nearly the whole length of the box, and on the inside, 



on each side, is a ledge or piece 

 of moulding to support slates to 

 be laid over the entire surface of 

 the box. The slates are sup- 

 ported by the ledges and by the 

 central partition, and should be 

 fastened down with cement to 

 prevent the propagating sand 

 from falling into the tank. One 

 slate is left out near the end, 

 next the fire, to enable the operator to see the water and to 

 keep it at the right level. On the slates sand is spread, in 

 which the cuttings may be struck, the sand nearly filling the 

 box. 



"At one end of the box is placed a common cylinder stove, 

 with pipe to the chimney. Inside the stove is a lead or iron 

 pipe (iron is the best) bent in a spiral round the inside of the 

 stove. This coil, which 

 is directly in the fire, 

 is connected by iron 

 pipes with the tank, 

 one pipe leading to 

 one side of the parti- 

 tion and the other to 

 the opposite side, as 

 shown in the drawing. 

 If water is placed in 

 the tank it will fill the 

 pipes and form a con- 

 tinuous circulating 

 system through the 

 pipes and up one side of the box past the end of the partition, 

 and down the other side. A fire in the stove causes the water 



Fig. 40. 



