Crane.| Prospecting, Mining and Milling Machinery. 275 
as itis almost universally employed by the small mine owners, 
and when properly handled is a very useful and efficient 
machine. 
It consists of a tank, A, well made and securely bound by 
plank and angle irons. ‘Two uprights or posts, B, are bolted 
to the middle of two opposite sides of the tank and rise above 
the same some 18 inches or 2 feet. They are notched at the 
upper end, so as to form a seat or bearing for the beam, C, 
to which is fastened a long lever or arm, D, braced by the 
pieces as shown at H. These braces, HL, project beyond the 
beam, C’, and support by hinges a long rectangular frame or 
box, #, which is the jig cell proper, and has a bottom made 
of gratings, the slots of which run at right angles to the sides 
of the box and are secured by grooves and bolts. 
Fig. 53. Plan of hand jig. 
The lever, G, is provided with a rod, H, formed into a hook 
at the outer end, which engages with the eye bolt, J, on the 
frame, F. This lever, when the hook and eye are engaged, 
being drawn back and locked behind the block, J, draws the 
jig cell, F, away from the side, K, of the tank, and so gives 
ample room for removal by shovel of the ore which has 
passed through the gratings. The gratings have one-eighth- 
inch spaces and are similar to those used in the power jigs. 
The tank is filled by a launder, and the height of water in 
itis maintained by an overflow, L, which drains into a launder, 
M. ‘The plug, N, located at the bottom of the tank, provides 
