1 
94 Modem Improvements in Com-Milliiuj Machinery. 
the working capacity of these latter machines is much smaller. I 
This roughly cleaned wheat is then conveyed to the granarv, i 
which for the economical handling of the wheat should be con- 
structed so as to contain a series of vertical bins or cells, hopper- , 
bottomed ; from these it may be drawn as and when required 
for use in the mill. 
Before being ground, the wheat must undergo a more thorough 
purification from extraneous matters and be subjected to a scouring 
process. It is easy to imagine that if the wheat be passed in a 
thin stream over sieves with the meshes or holes so aiTanered I 
that the wheat may just pass through, all matters larger than 
the wheat will be rejected ; and then if this wheat be passed over ^ 
another such sieve with holes arranged so as not to allow any 
wheat to pass them, all dust, sand, and small things would be | 
removed. If then the wheat be exposed to a current of air, | 
all defective corns, or things which are of the same size as 
but lighter than wheat, can be sucked or blown away. But it 
will be apparent that the holes in the coarse sieve must be 
larger, while those in the fine sieve must be smaller respectively 
than the smaller diameter of the wheat- corns, and consequently 
many things which are nearly of the same size and weight as 
the wheat-corns may pass with the wheat. Among such things 
are stones, bits of mud, barley, oats, rye, pease, vetches, and 
cockles, and the problem is how to get rid of them. I 
For this purpose, machines are used in the operation of which I 
the length of the wheat and other corns as distinguished from j 
those that are round is brought into play. The machines ! 
adopted for this purpose have for their principal member a ^ 
metal cylinder, the smooth surface of which, whether on the j 
interior or exterior, is pitted with hemispherical recesses of a 
diameter about corresponding with the small diameter of a 
wheat-corn. It is arranged that the stream of wheat shall be 
repeatedly brought into contact with the surface of the cylinder, i 
which is made to revolve slowly; in the holes all the round seeds 
or other matters lodge, and are carried up by the revolution of i 
the cylinder to a point where they roll or fall out, and as they i 
fall are intercepted by an arrangement which carries them out 
of the machine at a point separate from that at which the wheat 
is discharged. But as the wheat-corns would also enter these 
holes endwise and project, a light scraper is applied to the 
" pitted " surface, which knocks these corns out and they fall 
back to the stream of wheat. By changing the size of the 
holes the wheat may be picked up, and oats, barley, straws, or 
such-like things left behind. A variation of detail enables the ' 
operator to separate almost everything from the wheat. In i 
this department of cleaning machinery, very little remains to 
