84 Modern Improvements in Corn-Milling Machinery. 
the "middlings" consisted of the hardest and best part of the 
wheat. The difficulty was, however, the admixture with the I 
" middlings " of the chips of bran, and it was not until about | 
fourteen years ago that machines were brought into general 
use for "• pui'ifying " the " middlings." Up to that time it was 
sought to make as small a percentage of " middlings " as pos- ■ 
sible. Since the invention of the "middlings purifier," which | 
enabled the miller to obtain pui'e middlings, from which he I 
could make flour better than that coming from the original 
grinding of the wheat, the aim has been to make as large a per- ' 
centage of middlings as possible. And this principle of making 
middlings instead of flour is the basis of the new "gradual- ' 
reduction" system, the system now in vogue. 
One point or note of good grinding was the detachment of j 
the bran in large unbroken flakes, because the flour was more i 
likely to be pure than it Avould be if the bran were " cut up." 
The skin or bran of Avheat is more or less brittle, according to 
the variety of the wheat, if the grain be in equal condition. It 
may be laid down as a rule that the dryer and harder the wheat 
the more brittle the bran ; and it follows that the more brittle 
the bran the more apt it is to break up into small particles, which, 
passing through the same fine meshes of the sifting medium j 
as the flour, are inextricably incorporated with it. It ought to I 
be noted here that it is by no means only in the appearance of the 
flour that the mischief resulting from the presence of minute I 
particles of bran exists. That, commercially, is perhaps the 
least evil; for if the particles be very minute they are not so | 
readily perceptible as might be expected. It is especially when | 
the flour has been made into bread that the discolouration caused | 
by these particles manifests itself. It has been shown that they j 
cause a secondary and destructive fermentation, and that the I 
discolouration of the bread is due not only to the dark colour i 
of the particles themselves, but to their discolouring effect upon 
the flour with which they are mixed. Thus bread made from 
flour mixed with bran is, in appearance, a bread not like bread 
made from the same flour with flakes of bran in it, but the whole 
body of the loaf is stained, and browner than that made from flour 
without bran. Hence, as the colour of the loaf is the principal 
test of the good quality of the flour, the importance of keeping 
the bran unbroken, and therefore it follows that millers would j 
give the preference to wheats which, all other things being j 
equal, had the toughest skins, because the skins would be less ' 
likely to cut up. 
English wheats, in fairly dry condition, gave, because of the 
comparative toughness of tlic skin and the softness of the berry, 
which permitted the reduction of the fixrinaceous portion to 
