258 KESO URGES OF CALIFOENIA. 



now rarely seen, is a wooden trough about twelve feet long, 

 eighteen inches wide at the upper end, and widening at the 

 lower to thirty inches, with sides eight inches high. It is used 

 like a board-sluice, but has no riffle-bars, and at the lower end 

 its bottom is of sheet-iron, perforated with holes half an inch 

 in diameter. This sheet-iron is turned up at the lower end, so 

 that the water never runs over there, but always drops down 

 through the perforated sheet-iron or riddle, into a little riffle- 

 box, containing transverse riffle-bars. A stream of water of 

 about ten inches makes a " tom-head" — or the amount con- 

 sidered necessary for a tom — through the tom, which has a 

 grade similar to that of a board-sluice. The dirt is thrown in 

 at the head of the tom, and a man is constantly employed in 

 moving the dirt with a shovel, throwing back such pieces of 

 clay as are not dissolved, to the head of the tom, and throw- 

 ing out stones. From two to four men can work with a tom ; 

 but the amount of diit that can be washed is not half that of 

 a sluice. The tom may be used to advantage in» diggings 

 where the amount of pay-dirt is small and the gold coarse. 

 The riffle-box contains quicksilver, and as the dirt in it is kept 

 loose by the water falling down on it from the riddle above, a 

 large part of the gold is caught ; but where the particles are 

 fine, much must be lost. 



§ 191. Cradle. — The rocker or cradle is still less than the 

 torn and inferior in capacity. It bears some resemblance in 

 shape and size to a child's cradle, and rests upon similar rockers. 

 The cradle-box is about forty inches long, twenty wide, and 

 four high, and it stands with the upper end about two feet 

 higher than the lower end, which is open so that the tailings 

 can run oat. On the upper end of the cradle-box stands a 

 hopper or riddle-box twenty inches square with sides four 

 inches high. The bottom of this riddle-box is of sheet-iron, 

 perforated with holes half an inch in diameter. The riddle- 

 box is not nailed to the cradle-box, but can be lifted off with- 

 out difficulty. Under the riddle is an "apron" of wood or 

 cloth, fastened to the sides of the cradle-box and sloping down 



