432 Report on the Trials of Implements at Cardiff. 
chaff, and corn falling between them are swept back by the same action along 
the incline (6) to the shog-board (C), which also receives the corn and chafl" 
that fall through the concave (a), and passes them on to the riddle (C). The 
holes in this riddle are conical, with the largest diameter below to avoid 
clogging ; their upper diameter being j-inch for wheat and f-inch for barley. 
The surface of the riddle is grooved in the direction in which the cavings pass. 
Fig. 15. — Transverse section of a part of the Caving-riddle. 
The cavings are delivered on the ground behind the fore-wheels ; the chaff 
and grain falling upon the collecting-boards (D D) are passed over a fine metal 
screen which removes all weed seeds, and are next conveyed to the sieve, which 
occupies the lower part of the same frame (E) ; here a blast from the fan (F) 
separates the chaff and throws it upon the inclined perforated plate (G), 
through which the air escapes while the chaff slides down into a sheet-iron 
trough, in the bottom of which is a revolving screw (H). The screw conveys 
the chaff to the side of the machine, where it is caught up by a centrifugal 
lift and thrown into the receiving-box to which the chaff-bags are attached. 
The com falling through the sieve (E) is conveyed by the channel (E') to the 
receptacle below the corn-elevator cups (J J) ; these carry it up and deliver it 
to the chob-cleaner or hummeller (K), a conical cylinder, the interior of which 
is formed of rough surfaces. Inside this cylinder a small drum revolves, on 
the periphery of which are placed four or six beaters fitted with knives. By 
passing between the rough surface of the cylinder and the sharp beaters the 
grain is separated from the chobs or awns, which are subsequently removed 
by a cross blast which meets the com as it falls from the hummeller into the 
oscillating shoe (L). This shoe moves with the caving-riddle, to which it is 
connected by iron rods. The cross blast is obtained from the screw-shaped fan 
(M), which sends the current of air in the direction of its shaft. This form 
of fan has a considerable advantage over the usual one (where a cross blast is 
required), since it can be driven by a simple straight belt. From the shoe (L) 
the grain passes to the rotary screen (N), which consists of two separate 
cylinders of wire revolving on the same shaft, and so constructed that the 
spaces between each cylinder may be exactly adjusted by means of an eccentric 
on the shaft. The screen is self-cleaning and does not require brushes or 
wasliers behind the wires. From the screen the grain is delivered into sacl^s 
placed at the back of the machine. Two other points deserve notice. The riddle 
(C) and the shog-board (C) are suspended, not upon the usual wooden spring 
hangers, but upon hangers made of woven galvanized-iron wire. The action 
of the rotary shakers is assisted by the vibrating fork (0), which consists of a 
series of long bent iron teeth set in a rocking-bar placed across the frame and 
moved by the wooden connecting-rod (P) from the crank-shaft (Q), which 
oscillates the caving-riddle. By a recent improvement this vibratiug-fork has 
been fitted with an adjustment by which it can be set nearer to or further 
from the shakers. Whenever a thickened lock of straw passes from the drum 
it is caught by these teeth, which give it one backward and one forward 
shake before letting it go well spread out, to be carried in a series of light hops 
over the shaker rollers. If there is greater economy of power, as we think 
there must be, in the rotary as compared with the ordinary box shakers, it 
appears to be lost in some other part of the machine, for an inspection of 
column 22 (Tables I.-III.) shows that it absorbed rather more than the 
average taken by other machines. 
