p paper and tear it at the fold, it will tear easily; but if you
do the same thing with paper made of linen and cotton, you will find
it decidedly tough. Moreover, if you look closely at the torn edge of
the latter, you will see the fibers clearly. It is because of the
beating that the fibers are so matted together and thus make the paper
tough. While the pulp is in the beater, the manufacturer puts in the
coloring matter, if he wishes it to be tinted blue or rose or lavender
or any other color. No one would guess that this white or creamy or
azure liquid had ever been the dirty rags that came into the mill and
were sorted on the wire tables. Besides the coloring, a "filler" is
usually added at this time, such as kaolin, the fine clay of which
china is made. This fills the pores and gives a smoother surface to
the finished paper--a good thing if too much is not put in. A little
sizing is also added, made of rosin. Save for this sizing, ink would
sink into even the finished paper as it does into blotting paper.
After this, more water is added to the pulp and it is run into tanks.

Now the preparation is completed, and the pulp is pumped to large and
complicated machines which undertake to make it into paper. It first
flows through screens which are shaken all the while as if they were
trembling. This shaking lets the liquid and the finer fibers through,
but holds back the little lumps, if any remain after all the beating
and straining and cutting that it has had. The pulp flows upon an
endless wire screen. Rubber straps at the sides keep it in, but the
extra water drops through the meshes. The pulp is flowing onward, and
so the tiny fibers would naturally straighten out and flow with it,
like sticks in a river; but the wire screen is kept shaking sideways,
and this helps the fibers to interlace, and the paper becomes nearly
as strong one way as the other.

If you hold a sheet of paper up to the light, it will show plainly
what is next done to it. Sometimes you can see that it is marked by
light parallel lines running across it close together, and crossed by
other and stouter lines an inch or two apart. Sometimes the name of
the paper or that of the manufacturer is marked in the same way by
letters lighter than the rest of the sheet. Sometimes the paper is
plain with no markings whatever. This difference is made by what is
called the "dandy," a cylinder covered with wire. For the first, or
"laid" paper, the small wires r