thereby preventing the sheet from falling, turns both frisket and tympan, doubled up together

A, reservoir of ink. B, handle and cylinder, by turning which the ink is spread out. C, surface on which the inking roller, having been supplied with ink by cylinder B, distributes it. D, inking roller.

down upon the type, thereby putting the paper and type in contact, rolls the table in under the platen, and pulls over the bar handle, thereby squeezing the platen, tympan, paper, and type altogether, and effecting the printing. He then lets the bar spring back, rolls out the

table, unfolds the tympan and frisket, takes the printed sheet off the tympan, and lays it on the table beyond the unprinted paper. While he is removing one sheet, and laying on another, the second pressman inks the form again by running the roller over it. Thus they proceed continuously, until the whole of the number of sheets to be printed is worked off, at the rate of 250 sheets an hour, or four a minute. One side of the paper having been printed, the second form is worked, that is, the sheet is printed on the other side. The pages are kept back to back, or in register, by placing the points which hold the sheet on the tympan, through the same holes in the centre, used in printing the first side. When both sides are printed, the printed sheets are sent to the warehouse and hung up to dry, and as soon as the ink has hardened sufficiently, they are put between sheets of thin glazed pasteboard. The printed sheets thus separated from each other are placed in a book press. This is sometimes similar to a linen press, though hydraulic presses are generally used in large printing-offices. The object of this operation is to press out the indentations formed by the type in the paper. By pressing the sheets sharply in this way, they become perfectly smooth. When all the sheets forming the book are printed, they are gathered up and folded, and the binder makes them into books as they are sold in the shops.

The extensive operations of a large printingoffice, and the rapidity with which they are per

formed, may be shown by describing the production of the Official Catalogues, and other publications of the Great Exhibition of 1851. They consisted of four distinct works, a large Illustrated Catalogue in four volumes, and three small catalogues, one in the English language, the others in French and German. There were also some guide-books, lists, &c., of less importance. Messrs. Spicer Brothers, stationers, and Messrs. Clowes and Sons, printers, of London, contracted to produce these publications, at their own cost, looking to the. large sale of them for their remuneration.

The first thing done was to cast two sizes of

type. It was found that 58,520 lbs. were required, containing no less than 37,152,176 separate types or letters. The printing was to be commenced within six weeks, and, therefore, no time was to be lost in casting the type. Messrs. Clowes, who are type-founders as well as printers, finding that they could not cast such an enormous quantity of type quickly enough, obtained the assistance of several other type-founders in London and Edinburgh. The work went on without cessation, until it was completed; no sooner was one set of men tired, than another took their places, by night as well as day. Type-founding, like pin-making, is effected by a subdivision of labour amongst men and boys; one casts the letters in the matrix; another breaks off the superfluous metal which becomes attached to them in casting; another rubs the sides smooth; another places them in long rows, that they may be dressed, nicked, and bearded; and another arranges them in the order they are sold. In these operations 277 men and boys were employed; each relay of 20 men and 12 boys, making about 120,000 letters a-week. Whilst the type-founders were going on, the paper-makers were equally busy. No less than 627,698 lbs. of paper were required, and from the sorting of the rags to the production of the complete sheet of paper, 338 men and women were employed in making it. The iron-founders had also to make 800 chases, in

which the type is arranged in pages for printing; and the printers'-joiners had to provide 12,000 feet of furniture, and 12,800 quoins, for securing the pages in the chases. Finally, the ink-maker had to make 4000 lbs. of ink for the small Catalogues, 400 lbs. for the Illustrated Catalogue, and 1600 lbs. for the other publications—6000 lbs. in all.

In the preceding pages we have described. the printing of a book as proceeding, sheet by sheet, according to the plan generally pursued. But this was not the case of the Exhibition Catalogues; all the sheets, at least of the small English catalogue, twenty in number, were printed together, and almost at the same time. The copy of their intended contents could not be placed in the hands of the compositors according to the usual routine of authorship and printing, and thus occasioned extraordinary difficulties, which have rendered the successful termination of the work astonishing and highly honorable to the skill and industry of every one engaged in it.

The exhibitors, of whom there were 14,899, were each supplied with a blank form, in order that they might furnish descriptions of the articles which they intended to exhibit. The 14,899 descriptions thus obtained were placed in the hands of a body of literary men, who made corrections that were necessary in the wording, and divided the articles into thirty classes, each article being, of course,

any