CENTRIFUGAL TIIROWERS. 
225 
P y above. The bottom of the can is perforated like a grate with parallel 
slits, through which the bristles act, at g, to feed out the powder and to 
carry it around to where they spring from under the catch, o, to throw 
it forth in a cloud. The broader the slits in the base of the hopper the 
faster will it feed, and the amount to be used can be gauged by their 
width, which will vary some for the different kinds or mixtures of pow- 
der. The base, x, of the powder-can or hopper, P, may be attached only 
at one side, and there by a hinge, so that the brush, in rotating against 
it, will cause it to shake, and thus help the feeding process. Also a stiff 
part may be added to the brush, or its axle, to jar said base more effect- 
ually at each rotation. 
These devices are superior to perforated sifters, since they do not 
clog, while they throw a wider cloud. Also they may be used to throw 
powder upward, but not to a great height, for in this respect they are 
inferior to the blowers. This method is, however, applicable to poison- 
ing cotton, potato vines, &C., and worthy of being used in simple and 
Compound machines. Brushes arranged in the same way will throw a 
spray of water, which may be fed as described elsewhere. The most 
satisfactory of these ways is to have it drip from a spout without the 
automatic process. 
If the elasticity of the fibers is to be used, they should be sparse and 
turn slowly. If the throwing is to l>e done by the centrifugal force 
arising from rotation (which does better than by the elasticity), the 
velocity of rotation should be high (1, 0(H) revolutions per minute or 
more). The brushes rotated at 2,000 revolutions per minute made such 
a breeze that powder and liquid could not be fed onto them at the cir- 
cumference. Tliis was remedied by a circular disk of sheet metal placed 
on each end of the brush, and having the same diameter, to prevent the 
sir from feeding into the brash by central suction at the ends. Also, 
with, high velocity, the fibers should be exceedingly scattered and of the 
stillest sort. P>y this method, stiff wires, inserted so their points stand 
about one inch apart, form a reel, which works better than the corn- 
brushes. 
Mr. L. X. Wisewell, of Ottawa, Ontario, Canada, patented a brush 
machine in 1878 No. 211075), and which is illustrated in Fig. 3 of PI. 
XXVII. As shown, it possesses a form adapting it to poisoning potato- 
im rets ; but w ith some alterations a machine on similar principles might 
he constructed for poisoning cotton. A wheelbarrow is used as the 
motor and carrying device. The friction wheel, t, on the spring arm, 
a, is held against the side of the barrow wheel, being rotated thereby, 
and communicates its motion through its mandrel,/, pulley, j, and its 
belt, /,-, to pulley, /, and its axis, c, bearing the arms, b b, which act as 
agitators to keep the poison mixed in the tub-shaped reservoir. The 
liquid flows out through a cock, q, and its hose, into the semi cylin- 
drical cups, F. In these cups are the rotary brushes, n, made to whirl 
by the band, 1c, driven by a rim on the barrow wheel. The whirling 
63 cong 15 
