340 



BOOK VIII. 



A — Launder. B — Interlacing fir twigs. C — Logs ; three on one side, for the 



FOURTH cannot BE SEEN BECAUSE THE DITCH IS SO FULL WITH MATERIAL NOW BEING 



WASHED. D — Logs at the head of the ditch. E — Barrow. F — Seven-pronged 



FORK. G — Hoe. 



The third method of washing materials of this kind follows. Two 

 strakes are made, each of which is twelve feet long and a foot and a 

 half wide and deep. A tank is set at their head, into which the water flows 

 through a httle launder. A boy throws the ore into one strake ; if it is of 

 poor quahty he puts in a large amount of it, if it is rich he puts in less. The 

 water is let in by removing the plug, the ore is stirred with a wooden shovel, 

 and in this way the tin-stone, mixed with the heavier material, settles 

 in the bottom of the strake, and the water carries the light material into the 

 launder, through which it flows on to a canvas strake. The very fine tin- 

 stone, carried by the water, settles on to the canvas and is cleansed. A low 

 cross-board is placed in the strake near the head, in order that the largest 

 sized tin-stone may settle there. As soon as the strake is filled with the 

 material which has been washed, he closes the mouth of the tank and continues 

 washing in the other strake, and then the plug is withdrawn and the 

 water and tin-stone flow down into a tank below. Then he pounds the sides 



