electrotype plates are used. The sheets are "fed" by hand in the usual
manner, and are printed on one side at a time and delivered by a
sheet-flier. It produces as much work as four flat-bed cylinder
presses and of better quality. The plates are inked by sixteen
rollers. The performance of this press is another demonstration of the
superiority of the rotary over the flat-bed principle of printing.

Since then hundreds of rotary presses have been made for magazine and
book printing, most of them equipped with attachments for folding the
sheets as they are printed, and all having a high rate of speed. C.
B. Cottrell & Co. have made many rotary presses for magazine printing,
most of which deliver the sheets flat, without folding, and most of
them made to suit some predetermined size or sizes of sheets or pages.

In the evolution of the printing press there are three sharply defined
stages: first, the flat impression surface and the flat printing
surface, requiring the exertion of all of the impressing power upon
the entire surfaces; second, the cylindrical impression surface and
the flat printing surface, requiring the exertion of all of the
impressing power upon only a narrow line or a small portion of the
printing surface; third, a cylindrical impression surface and a
cylindrical printing surface, still further reducing the area upon
which all the impressing power is exerted.

Just as the second stage has, particularly for book-work, virtually
superseded the first, so the third is destined to supersede the
second. It is only an adaptation of the means to the ends. The
mechanical principles of the rotary press are, in fact, simpler than
those of the flat-bed cylinder press, and it may be said that so far
as the purely mechanical part of the press is concerned, they have
been fully developed, but much still remains to be done in other
directions. The variety in the sizes of the pages of different books,
the smallness of the editions, and the fact that the finer grades of
paper, especially coated paper, cannot be obtained in roll form, are
obstacles to be removed. As most book forms are electrotyped for
flat-bed presses, and as it requires but little additional expense to
curve the plates, this one item is not much of an obstacle to
overcome. It is, however, still difficult to curve the plates
perfectly, and the pressmen, even if they can produce excellent work
from flat-bed presses, require considerable training if the