s mechanism which is in use even at the present time, and is
described farther on, when the two-revolution press is mentioned. The
different parts were not connected with each other, the cylinder, the
type-bed, the inking-rollers, and the fountain being operated
independently by separate driving mechanisms. This press printed eight
hundred sheets an hour, on one side. A part of Clarkson's "Life of
William Penn" was printed on this press, and was the first book ever
printed on a cylinder press.

Printers and publishers were sceptical as to the practical value of
this novel invention, but Mr. John Walter, the proprietor of the
_London Times_, with better foresight than the others, and needing
increased facilities for printing his paper, contracted for two
presses, each to have two impression cylinders. These were constructed
for him with great secrecy in a building adjoining the pressroom of
the _Times_, and on November 28, 1814, the entire edition of that
paper was printed on them,--the first cylinder presses driven by steam
power.

The mechanical principles were the same as in the first cylinder
press. There were two impression cylinders, but only one type-bed, and
the latter had, therefore, to travel a greater distance than in the
single-cylinder press. This made it impossible to obtain quite double
the output of the single-cylinder press, but each of these new presses
produced eleven hundred impressions an hour, a very respectable
performance for that early stage. The threefold motion of the
cylinders was retained, but the frisket frames were displaced, and
tapes running over rollers and underneath the cylinders held the
sheets against the impression surfaces. An improvement was also made
in the inking mechanism by the addition of an intermediate roller
between the fountain and the upper distributing cylinder roller.

The next step in advance was the construction of the first of the
so-called perfecting presses, which was patented, December 24, 1814,
and erected in Mr. Bensley's office in 1815 or 1816. This press had
two type-beds and two impression cylinders, one of each near either
end of the press. The cylinders instead of having a threefold motion
revolved continuously. The circumference of each corresponded
approximately to the distance traversed by one of the beds. The part
of the cylinder which made the impression was a little larger in
diameter than the remainder, the low portion giving the necessary room