BEATING COTTON 99
they are firmly bound together by the fibrillae, they serve to prevent the close
packing of a more highly fibrillated paper. At the same time the wetness or
fibrillation of the other fibres allows the dandy roll to make a good impression.
Thus we have the natural strength, bulk and opacity of the long fibres, and
the felting strength and clear water-mark given by the fibrillae.
While we have this illustration before us, we may just touch on a point
in beating which seems to have been overlooked by many so-called beating
experts, who seem to consider that the perfection of beating is to have the
fibres of a uniform length. This is true only so far as the beating for printing,
litho and such-like papers is concerned. But the ideal ledger paper, and indeed
many other papers, cannot be properly made by fibres beaten to a uniform
length. This is one of the factors that have kept the hollander beater in the
highest pkce as an efficient beating engine. Its irregular and unequal circula-
tion, even in the best designs, ensures that-many fibres are little touched, while
others may be driven through the nip many times.
Unless there were a fair proportion of long fibres to form the framework
of the sheet, there would not be much strength and bulk, and without the fine
fibrillae there would be poor water-marking and felting.
Reverting, however, to our writing-paper example, uniform length of staff
is of more advantage, because strength may be considered of secondary impor-
tance. The fibres being cut to produce fine stuff still retain their original charac-
teristics, opacity and bulk. The quicker ckcuktion of the less concentrated
and lighter-charged beater will ensure that fewer fibres escape being cut
Cotton beaten quickly— Le. cut fine—carries the water well up to the dandy
roll owing to the close packing of the fibres. The roll makes a good im-
pression because there are fewer long fibres to prevent the sinking in of the
protruding letters or designs. After passing the dandy roll, however, the suction
boxes are seen to take die water out of the sheet very easily, showing that
little fibrillation has taken place in the beater.
If, however, we intend to make our writing paper of thinner substance,
say 18 Ib. Large Post, we have to alter our beating a little. We must fill in
more stock and allow a little more time to beat, so that we may have some
long fibres and more fibrillae, to help to run the paper over the machine, without
having breaks and 'pick ups' at the dandy roll We can do this because the
thinner substance allows and requires more water to be used on the machine
to close up the sheet, and the impressions of the dandy roll are more trans-
parent. From this a step further, higher concentration of stuff and still longer
time beating, give us stock suitable for a bank paper of 15 Ib. Large Post, and so
on down to thin banks of II Ib. and under.
Reversing the process, as we increase the substance of our paper to, say,