The Trials of Grist Mills and Disintegrators at Plymouth. 613 
is grooved parallel to its axis with straight flutings about f inch 
pitch and | inch deep, and revolves, at a speed of 450 per minute, 
against similar Antes in a concave, also of hard white iron, which 
occupies the whole length, and half the circumference of the 
grinding cone itself. The concave is adjusted for coarse or 
fine grinding by means of set screws, which raise or lower it in 
parallel guides, and the two are trued up by grinding together 
with sand — a method which, it need scarcely be said, does not 
insure truly circular surfaces in either roller or breast. The mill 
is driven by strap direct, and the grain admitted to the small 
end of the grinding-cone. Thence it passes, more or less slowly, 
along the incline of the conical breast, till it is at length dis- 
charged as meal from the end of the mill. 
A good deal of re-grinding necessarily takes place in the 
" Felton " mill, and showed itself on this occasion in heated 
meal, comparatively slow grinding, and heavy draught. Fine 
samples were produced, and although points were lost in the 
directions indicated, it is but fair to say that the Barford mill 
ran the second prize mill hard, the difference between the two, 
as determined by summing the points of merit, being only 3| 
per cent. 
Table III. 
Name of exhibitor 
Cata- 
logue 
No. 
Material 
Quan- 
tity of 
material 
Time 
occu- 
pied 
Total 
units of 
power 
consumed 
Units of 
power 
required 
per cwt. 
Quan- 
tity of 
material 
per hour 
Mean 
horse- 
power 
Corbett & Son . . . 
3460 1 
Maize 
Oats 
Barley 
lb. 
H 
minutes 
2- 33 
3- 66 
327 
562,120 
480,197 
495,321 
1,124,240 
960,394 
990,642 
lb. 
1,442 
918 
1,027 
7-31 
397 
459 
Woodroffe & Co. . . 
3441 | 
Maize 
Oats 
Barley 
M 
213 
2-0 
347 
482,718 
265,936 
603,712 
965,436 
531,872 
1,207,424 
1,577 
1,680 
968 
686 
4-03 
527 
Barfor'l Si Perkins . . 
2420 j 
Maize 
Oats 
Barley 
H 
328 
365 
4-58 
1,203,644 
472,635 
1,380,094 
2,407,288 
945,270 
2,760,188 
1,024 
920 
733 
11 12 
3-92 
913 
Bamfonl & Sons . . 
33CC | 
Maize 
Oats 
Barley 
H 
4-25 
305 
333 
714,624 
507,925 
1,025,933 
1,429,248 
1,015,850 
2,051,866 
790 
1,101 
1,009 
509 
5 04 
9-30 
Blackstone i Co. . . 
2565 -j 
Maize 
Oats 
Barley 
M 
6-75 
453 
658 
1,638,468 
733,529 
1,618,302 
3,276,936 
1,467,058 
3,236,604 
497 
741 
510 
735 
490 
7-45 
CLASS 3. — Disintegrators. 
Judges. 
Dan. Pidgeon, C.E., "\Valsin<?ham House, Piccadilly. 
Prof. W. 0. Unwin, F.R.S., 7 Palace Gate Mansions, KensiDgton. 
Prizes offered: First, 20/., Second, 10/., for Disintegrators, suitable for 
•working with a portable or traction engine not exceeding 20 horse-power. 
