FIBROUS MATERIALS 3

the tube collapses on itself and takes on a twisted form, something like a cork-
screw, or a rubber tube which has had the air sucked out of it. This peculiar
formation is of great interest and value to the paper-maker.

The fibre has a thin outside wall and a wide canal. The twisted, corkscrew
form taken up by the cotton fibre is very characteristic, and may be clearly
seen in the illustration. This is the chief reason why cotton produces a paper
that is soft, flexible and bulky. The fibres will not pack closely together as

Shraw

FIG. i.—THE FIBRES OF COTTON, LINEN, ESPARTO, AND STRAW, WITH CHARACTERISTIC CELLS

flat fibres do. They are opaque, white in colour, with no pores or cross-
markings, and the ends are round, blunt points.
In the process of paper-making, the appearance of these fibres is very much
altered. The blunt ends are often destroyed, and are rarely seen under the
microscope. The curious twist is not so prominent, and the fibres are topi
and shredded.
Although, as mentioned already, cotton fibres will not lie closely togsdb®£
owing to their twisted formation, nevertheless, under the influence of tfeeAfw: