CrRANE.| Prospecting, Mining and Milling Machinery. 299 
apparatus, and is quite large, ranging from six to twelve 
feet in length and from four to six feetin width. The course 
of the slimes through the tank is shown by the arrows. 
The forms of classifiers illustrated above are of the spitz 
lutte type, and in many cases, as used, are intended only as 
stay boxes; 7. e., are employed as means of holding back and 
maintaining a certain head of water in the jig, and not em- 
ployed at all as classifiers. This is not the case, however, 
with the last-mentioned form, which is employed exclusively 
as a settling box or classifier. 
Y f \ N " 3 3 
(} N NN \ 
ft N \ N \ 
yy 
a ont 
4 y \ N \ 
pt Poe teas 
ot i | 
PLyPe Ee yey ey] 
Fig. 76. Unwatering box. 
THE HYDRAULIC SEPARATOR. 
Several forms of hydraulic separators or classifiers have 
been employed in the district, all of which represent forms 
in common use in other parts of the country. A form com- 
monly employed in the district will be taken as typical of 
those in use. 
In figures 75 and 74 are shown a top view and vertical section 
of a hydraulic classifier. It consists of two four-sided pyra- 
mids, constructed out of one inch soft pine boards, one of 
which, A, is placed within the other, B, and both inverted. 
The outer pyramid is about eight inches larger across the base 
than the inner one; the sides of both are, however, parallel. 
The inner pyramid, A, is truncated, 7. ¢., just the tip of the 
apex is cut off, which leaves an opening about one inch square, 
E. The two pyramids are spaced the proper distance apart 
and fastened in that position. A discharge opening, or spigot 
20—Viii 
