278 University Geological Survey of Kansas. 
Another method of joining the timbers at the corners of 
the jig is shown at 2, figure 58, which is stronger than the 
form shown at 7, but isnot much used and is more expensive. 
Fig. 58. Methods of putting together jig tanks. 
If the jig is to be six-celled, five partitions are placed trans- 
versely and at equal distances apart. ‘These chambers are 
again subdivided by a partition extending about half way 
down from the top (figure 57), thus subdividing the top 
portion of the jig body but not the lower. The two series of 
compartments or cells thus formed are connected at the bot- 
tom, and the whole space at the bottom of the two connected 
cells is formed into a hopper, which is constructed in a num- 
ber of ways: (1) It may be regular, in which case all of the 
sides slope inward to the center of the bottom of the rectangu- 
lar space formed by the bottom of the two cells. The oppo- 
site sides will have the same slope, but the sides fore and aft 
(or ends) will have a slighter inclination than the lateral 
slopes. (2) One side or end, usually the back, may be much 
elongated. Figures 55 and 57. 
In some cases the front side of the jig may form the front 
end of the hopper, while the slope of the back side extends 
clear across the bottom of the two cells, in which case it is 
