DRESSING OF ORES 



145 



B, inclined plane upon -which the stuff is lodged. Clean water flows over the ledge c. 

 When the table A is turned in a vertical position, the racking girl washes it by de- 



743 



pressing the lever E attached to the V-shaped launder D, thereby discharging the 

 water which it may contain. The heads, middles, and tails are lodged in the com- 

 partments F, o, and H, respectively. 



The Machine Frame, fig. 744, consists of an inclined table, about 8 feet long and 



5 feet wide, with sides 5 inches high. At each end are fixed axles of iron, A B, which 

 are centred in two vertical pieces of timber c D, and admit of the frame being turned 

 perpendicularly. At the head of the frame is a ledge B, on which numerous lozenge- 

 shaped pieces of wood are fixed in order to distribute the liquid stuff on the entire 

 width of the frame. 



From the frame head, the stuff falls on a sloping board F, which admits of being 

 turned, as it is hung by leathern hinges, when the frame assumes an upright position. 

 At one of the bottom corners of the frame is a box o, into which the chief part of the 

 water from the table flows. In operating with this machine, the liquid matter is 

 admitted to the frame head B, through the hole H, and flowing in a thin sheet on the 

 table i, deposits the vein- stuff according to its varying specific gravity, the best quality 

 being heads from 1 to 2, the middles from 2 to 3, whilst the tails are lodged at the end 

 of the apparatus. To the water wheel is attached a horizontal axle fitted at given 

 distances with cams, which disengage at the proper time parts of the machinery 

 connected with the frame. The first cam acts on the rod K, and stops the flow of tin 

 stuff; the second cam disengages a catch beneath the displacing box G, containing 



VOL, II. L 



