r paper, it is run through a
series of alternate "chilled" and "paper" rolls. The chilled rolls are
made of steel and have a very smooth and even surface. The "paper"
roll is made of circular discs of thin, but strong manila paper,
clamped together on an iron shaft, and then put under hydraulic
pressure, this pressure being increased constantly until it reaches
one hundred tons of pressure to the inch. The rolls are sometimes kept
under this pressure for five or six weeks, and then are turned on a
lathe into a true and smooth cylinder, and finally burnished by being
revolved against each other.

A "cotton" roll, used at times in place of the "paper" roll, is made
in the same manner, except it is made of pieces of cotton cloth
instead of thin manila paper. There is a heavy pressure on these
rolls, and the paper goes through at a high rate of speed. When an
especially smooth surface is wanted, steam is run on the paper as it
unwinds, dampening it and giving the web a surface like that on ironed
linen.

"Coated" paper is treated differently, being covered with a fine
coating, which, after super-calendering, gives the paper a glazed and
smooth surface for fine half-tone illustrations. Clay, mixed with
casein, the product of skimmed milk, or glue, is the chief material
used for coating. It is put on the paper by means of large brushes.
Then it is dried by fans and passed through a long passageway heated
by steam to a high temperature. After being reeled, it is allowed to
stand for a while to harden; then is run several times through the
calenders to get the smooth surface. If a high, glazed finish is
necessary, steam is put on while running through the calenders. This
gives a very bright surface for fine lithographic work. For the best
coated papers, instead of clay, sulphate of lime and sometimes
sulphate of barium is used, with glue or casein. Formaldehyde, a
chemical compound, is used to prevent decomposition in the coating
materials; and soda or borax is used to "cut" or dissolve the casein
or glue.

If the paper is to be printed "from the web," that is, from the roll,
it first has to be trimmed to the correct width, then wound tightly
under a high pressure to a certain thickness, then the rolls are
packed up in wrapping paper ready to be shipped. Some rolls contain as
much as five miles of paper. When the paper is to be put up in
sheets, it has to be cut to exactly the correct width and length on
the cutting machin