when united with the ordinary matter, eight-and-forty columns, re-appear in regular order on the platform of the printing-press. The hand of man is now too slow for the demands of his curiosity, but the power of steam comes to his assistance. Ink is rapidly supplied to the moving types, by the most perfect mechanism;—four attendants incessantly introduce the edges of large sheets of white paper to the junction of two great rollers, which seem to devour them with unsated appetite;—other rollers convey them to the type already inked, and having brought them into rapid and successive contact, re-deliver them to four other assistants, completely printed by the almost momentary touch. Thus, in one hour, four thousand sheets of paper are printed on one side; and an impression of twelve thousand copies, from above three hundred thousand moveable pieces of metal, is produced for the public in six hours.
(333.) The effect of machinery in printing other periodical publications, and of due economy in distributing them, is so important for the interests of knowledge, that it is worth examining by what means it is possible to produce them at the small price at which they are sold. "Chambers' Journal," which is published at Edinburgh, and sold at three half-pence a number, will furnish an example. Soon after its commencement in 1832, the sale in Scotland reached 30,000, and in order to supply the demand in London it was reprinted; but on account of the expense of "composition" it was found that this plan would not produce any profit, and the London edition was about to be given up, when it occurred to the pro-
