Report on the Trials of Implements at Cardiff. 
431 
(A A) is a slieet of charcoal plate-irou enveloping the drum, and lightened 
by the perforations (B B). At the angles of tlie hexagon the ribs of the beatcr- 
bars (C C) project through the iron plate. The bcater-bars are kept in their 
places by the set-screws (D D), which arc tapped into the cast-iron heads (E E), 
keyed upon the drum-spindle. The screws press against the back of the beater- 
bar.'i, and these, pressing against the internal surface of the iron sheet, keep it 
stretched out and rigid. The beaters are made in segments of 6 inches each, 
■and all that is needed for replacing any one of them is to slacken the single 
set-screw that holds it in position. The beaters are of cast iron, the ribs or parts 
projecting through the hexagon being " chilled." The entire drum being of iron 
and symmetrical, the balance, when once obtained, is not liable to be disturbed 
by climate or temperature. The concave (Fig. 14) used in combination with the 
above drum is composed of malleable-iron gratings (A A), and wrought-iron 
bars (BB), alternately bolted together in such a manner that they may be 
readily taken to pieces, and the wrought-iron bars turned round to present tlie 
other edges to the action of the drum when the first becomes worn. The 
Fig. 14. — Section (I.) and Plan (IT.) of part o f the Concave used with 
Brinsmead's Patent^Sexagonal Drum. 
I. II. 
gratings have square apertures of such size as to prevent the passage of 
imthreshed broken ears, but still affording ample space for the escape of the 
grain. Eight curved bolts (DD) passing through the gratings and the bars 
hold the parts of the concave together. The drum being closed instead of 
open, will have more of a rubbing, and less of a beating, action upon the 
corn than the usual form of drum. It thoroughly extracted the corn in 
the trial, but must, we think, absorb more power than the open drum ; this 
point, however, we were not able to test by direct experiment. 
The passage of the grain and straw from the drum and the arrangement of 
the other parts of the machine are shown in Fig. 16 (p. 433), a longitudinal sec- 
tion. The straw passing from the drum is thrown upon the rotary straw shaker, 
formed of fifteen revolving triangular rollers (B) having fixed upon each of their 
edges a series of curved iron teeth, so arranged that the teeth of each roller 
shall clean themselves by passing between the teeth of the rollers on each side 
of it. These teeth toss the long straw upwards and forwards, while the cavings, 
