Trials of Self-binding Reapers at Aighurth. 
135 
loosely fitted a bell-shaped metal matrix, B, 6 in. in its smallest diameter and 
10 in. in its greatest. This constitutes the driving part. Its surface is deeply- 
grooved at the top for kibblini; purposes, and finely lined at the bottom for 
grinding into flour. It revolves inside a concave, D, similarly grooved, but 
cut the reverse way. The position of the matrix with the concave is altered by 
means of a hand-wheel and levers, which raise or depress it at will, and adjust 
it for grinding fine or for kibbling, with the peculiarity of allowing the grind- 
ing surfaces to remain idle when kibbling only is required. A safety provision 
is made for allowing the passage of any foreign hard substance, such as a nail 
or stone introduced with the feed, without injury to the grinding part. The 
feed is regulated by means of a ferule fixed at the bottom of the hopper, and 
riding on the crown of the matrix. This can be readily set to a nicety by a 
simple combination of lever, hand-wheel, and screw. 
The special advantages claimed for the mill are : — 
1. That the matrix and the concave, the principal wearing parts, are small, 
inexpensive, and require no fitting when it is necessary to replace them. 
2. That the grinding being carried on over the whole surface of the concave, 
it wears evenly and not in holes ; and the system of vertical adjustment ensures 
its grinding thoroughly until worn quite smooth. 
3. That owing to the safety arrangement the liability to breakage of the 
concave is reduced to a minimum. 
4. That the mill will grind all kinds of com and pulse equally well. 
Fig. 8. — Section of Nicholson's Patent Grist Mill. 
A. Vertical spindle, on which is the 
fly-wheel and driving-pulley. 
B. Hard-metal bell or cone sus- 
pended freely on spindle, hav- 
ing coarse grooves in the 
upper part, meeting grooves 
in the concave for kibbling, 
and finer grooves cut the 
reverse way for grinding into 
meal. 
t, 6,5. Feathers for causing a 
current of air throuah the 
mill, and carrying the grist to 
the delivery spout C. 
D. The fixed metal concave, grooved 
the reverse way to the cone B. 
E. Nozzle or ferule for regulating 
the feed, screwed into the 
dome (/) and held in any 
required position by a jointed 
lever (g), dropping into 
notches in the upper flange 
of the dome. 
J. Hopper. 
K. Oil-cup for lubricating the 
spindle where it passes 
through the 8tu£Bng-box S. 
This machine worked admirably under every test to which it 
was submitted. The invention is remarkable for the sim- 
I 
