But the printing machine would have worked feebly and imperfectly without the paper machine. That most complete invention has not only cheapened paper itself, but it has cheapened the subsequent operations of printing, in a remarkable degree. It has enabled one revolution of the cylinder of the printing machine to produce four sheets instead of one, or a surface of print equal to four sheets. When paper was altogether made by hand, the usual paper for books was called demy; and a sheet of demy produced sixteen octavo pages of a book. The paper could not have been economically made larger by hand. A sheet of paper equal to four sheets of demy is now worked at the newspaper machine; and sixty-four pages of an octavo book might be so worked, if it were needful for cheapening production. Double demy is constantly worked for books. Thus, one economical arrangement of science produces another contrivance; and machines in one direction combine with machines having a different object, to produce legitimate cheapness, injurious to no one, but beneficial to all. Let us attempt to convey a notion of the beautiful operations of the paper-machine. In the whole range of machinery, there is, perhaps, no series of contrivances which so forcibly address themselves to the senses. There is nothing mysterious in the operation; we at once see the beginning and the end of it. At one extremity of the long range of wheels and cylinders we are shown a stream of pulp, not thicker than milk and water, flowing over a moving plane; at the other extremity the same stream has not only become perfectly solid, but is wound upon a reel in the form of hard and smooth paper. This is, at first sight, as miraculous as any of the fancies of an Arabian tale. Aladdin's wonderful lamp, by which a palace was built in a night, did not in truth produce more extraordinary effects than science has done with the paper-machine. [Illustration: Paper-making by Hand.]