CraneE.| Prospecting, Mining and Milling Machinery. 279 
given as great an inclination as is possible. In all cases, the 
two sides of the hopper have the same inclination. 
The hopper is to catch the fine ore that passes through the 
screen as well as to facilitate the discharge and emptying of 
the cells. ; 
SSN 
SHAMNAAAAANT JAAN AAA SSSA 
AMMAN, AAW AASSSNE SSA 
2 
‘ 
TENE DQG’ AQAAPAL SSS SSS: SSS 
Fig. 57. Transverse section of power jig. 
The front row of cells, as B, figure 55, formed by the longi- 
tudinal partition, A, is called the sieve cells, while the back 
row, as C, is called the plunger cells. The former carries 
the gratings or screens on which the ore rests, and vary in 
size from 28 x 30 to 80x42 inches. (See 7, figure 65.) 
The shaft, NO, which is broken at K, to allow two different 
speeds, is mounted in bearings on the caps of the frames, Z. 
Kecentrics, a, b, c, d, ¢, and f, are keyed or set-screwed to the 
shaft, NO, directly above the center of the cells (plunger), 
and are connected with the plungers by pitman rods, F; 
thus, as the shaft revolves the plungers are raised and 
lowered in their respective cells. For details of eccentrics, 
see figure 61, where 7 is a sleeve fastened to the shaft, NO, 2 
is a sliding circle or hub, which is fastened to 7, 3 is a cast- 
