Modern Imp'ovements in Corn-Milling Machinery. 101 
It has already been said that the purpose of the first stage 
of the system is to break the farinaceous portion of the wheat 
into small fragments and to avoid making flour. This end is 
accomplished by a series of " breaks," varying in practice from 
four to eight, the number most generally used being six. The 
invention and development of the " roller mill," and especially 
the adoption of chilled iron as the material for rollers, has in- 
coutestably left the field in possession of that machine as the 
best instrument that has hitherto been employed for the purpose. 
The rollers employed for the breaks are grooved, generally so as 
to leave teeth with a sharp edge, the grooves varying in number 
from eight up to thirty to the inch. The operation of the breaks 
is thus conducted : — 
The wheat is passed through the first machine, and the 
broken pieces, then called " chop," are carried to a sifting reel 
covered with coarse wire cloth, which allows all flour and small 
fragments to pass through. What will not pass through is fed 
to the second " break," which reduces the material to smaller 
fragments and opens and spreads out the bran. This " chop " 
is taken to anothei' reel for the removal of all its finer parts, 
and what remains goes to the third break, and so on through 
the series, each succeeding roller-mill having rolls with finer 
grooves than its predecessor, and the rollers being set so as to 
leave less and less space between them. From the last roUei'- 
niill the bran should emerge freed from all flour-bearing cells. 
The reels by which the fine stufi" is sifted out between each 
break are termed " scalpers." Recently, horizontal sieves have 
been 'introduced to take the place of reels in the scalping 
operations. 
Ideal perfection of the breaking process would leave the bran 
in large unbroken flakes, freed from all the flour-bearing cells of 
the interior, and the farinaceous portion of the wheat should be 
found in small pieces, and no flour should have been made in this 
stage of the process. But in the practice of the mill the results 
obtained are very far short of this ideal perfection. In actual 
practice the products yielded by the breaking process are bran, 
a considerable percentage of flour when tender wheats are used, a 
less percentage from hard wheats, and " semolina," " middlings," 
and very fine middlings called " dunst." These three last are 
the gritty particles of the interior of the wheat, which, after 
"purification," under further treatment to reduce them to flour 
by smooth rollers, yield the finest flours. 
The bran and the flour from the breaks are finished com- 
j mercial commodities. The first operation after the breaks is 
i a sifting process, to separate the gritty products from the flour, 
by means of appropriate dressing-machines. But, as has been 
