Crane.| Prospecting, Mining and Milling Machinery. 281 
ing or strap enclosing the circle 2, to which is fastened the 
plunger rod, kK. By means of the slots, the length of the 
stroke may be varied. 
Pulleys, X, one to each section of the shaft, NO, are usually 
keyed near one end of each section. The pipes, Y, connect 
the hopper with the outside or front of the jig, and discharge 
through spigots into the trough, J. The pipes, M, admit wa- 
ter into the plunger cells, through the launder, A,. Discharge 
pipes maintain the proper level of the water in the plunger 
cells. The launder, B, feeds the jig. A settling box and over- 
flow regulator are shown at 0Q,. 
The screen surface may be grating (/, figure 62) or wire 
cloth on the rougher jig and wire cloth on the cleaner and 
sand jigs. Occasionally only the first few cells of the rougher 
jig are provided with grating, while the remaining cells are 
furnished with wire cloth. Usually the cleaner jig is furnished 
throughout with wire cloth, yet, in a few instances, fine grat- 
ings have been observed on the first cell or two. As arule 
the rougher jig is provided with one-eighth-inch gratings, 
while the cleaner jig may have ail cells furnished with five 
mesh wire cloth, or the first cell four, the three following five, 
and the last six mesh. The sand jig has ten to twelve and 
fourteen mesh in all but possibly the first one or two cells, 
which may have six or eight. 
When wire cloth is used, a support must be provided (2, 
figure 59), which is made of thin strips of wood, mortised 
together. The wire cloth is usually fastened to this frame- 
work by nails or screws, and is easily removed when repairs 
are necessary. 
Spigots are provided at the bottom of the front side of the 
jig. and are screwed into openings or pipes, making direct 
connections with the hoppers in the bottom of the cells. The 
material which falls through the bed and screen above settles 
into these hoppers and is call the ‘‘ hutch,’’ which can be run 
off at will through the spigots connecting with the same. 
The spigots are so arranged in the cleaner that the ore and 
water are thrown back against the end of the foot trough, J, 
z. €., opposing the flow from the same, while in the rougher 
the flow from the spigots aids the flow from the trough. 
