Report on the Trials of Implements at Cardiff. All 
falls from the hopper into the stone separator — a box fastened nixiu tlie screen- 
frame, with a bottom of wire-net of large gauge ; this intercepts all foreign 
substances larger tlian the gi'ain, and delivers them out of a spout at the side. 
The corn passing through the meshes of the separator then descends over the 
surface of the screen in a thin broad stream, rippling over the cleaning collars : 
this rippling action changes the position of each grain, and gives it a longi- 
tudinal direction in its passage, greatly facilitating the extraction of thin 
and broken grains. 
Fig. 32. — Bohy's Neio Patent Self-acting Corn Screen. 
No. 3732. S. Bohy. — A self-acting machine, worked by tlie weight of the 
grain acting upon a breast-wheel placed between the hopper and the screen. Two 
cranks upon the axis of this wheel are on each side connected by rods to two 
light frames, each carrying four rows of the cleaning collars ; these working 
between the wres of tlie screen keep them clean. No attention is required 
beyond that of keeping the hopper supplied with grain, and it is recommended 
as a great economiser of labour. 
The idea is novel and ingenious, but not of much practical value in its present 
mode of application ; it affords, however, a simple illustration of the significance 
of the figures given in column 10 of Table X. These figures show that the 
other screens varied, in the power required to drive them, from 16 to 50 foot- 
pounds per pound of corn screened, the manual labour being expressed by the 
height in feet from which the corn would have to fall in order to produce force 
enough to do the work. In this machine the work is actually attempted to be 
done by raising the bottom of the hopper about one foot above the top of the 
screen, and then introducing a wheel to irtilize the force so obtained. 
It is at once obvious that there must either be a great waste of power in the 
other machines, or that the power employed in this case is not nearly enough to 
secure efficient work. In all the other machines, the screen itself either oscillates 
