Printing.

to be conducted until the middle of the The tage from mechanical ingenuity. Originating at the middle of the 15th, the art continued 17th c. in a very clumsy manner. press resembled a screw-press, with a contrivance for running the form of types under the point of pressure; force having been thus applied, the screw was relaxed, and the form withdrawn with the impression executed on the paper. The defects of this very rude mechanism were at length partially remedied by an ingenious Dutch mechanic, Willem Jansen Blaeu, who carried on the business of a mathematical instrument-maker at Amsterdam. contrived a press, in which the carriage holding the form was wound below the point of pressure, which was given by moving a handle attached to a screw hanging in a beam having a spring, which spring caused the screw to fly back as soon as the impression was given. This species of press, which was almost entirely formed of wood, continued in general use in every country in Europe till the beginning of the present century. With certain lever powers attached to the screw and handle, it is represented above.

FIG. 1.-Old Common Press.

He

In connection with this representation of the old common press, the process of printing may be described. The form, being laid on the sole of the press (s), is fixed at the sides, so as to render it immovable from its position. There are 2 men employed; one puts ink on the form, either by means of stuffed balls or by a composition roller (see illus., plate I., figs. 10, 11), and the other works the press. The latter lifts a blank sheet and places it on what is called the tympan (t), which is composed of parchment and blanket-stuff fitted in a frame and tightened like the top of a drum-and hence its name and which, by means of hinges connecting it with the sole, folds down like a lid As the sheet, however, would fall off in the act of being brought down, over the form. a skeleton-like slender frame, called a frisket (f), is hinged to the upper extremity of the tympan, over which it is brought to hold on the paper. Thus, the frisket being first folded down over the tympan, and the tympan next folded down over the form, the impression is ready to be taken. This is done by the left hand of the pressman winding the carriage below the platen (p), or pressing surface, and the impression is performed by the right hand pulling the handle attached to the screw mechanism. The carriage is then wound back, the printed sheet lifted off, and another put on the tympan, the form again inked, and so on successively. In the above engraving, the press appears with the frisket and tympan sloping upward, ready to receive the sheet, the frisket being sustained from falling backward by a slip of wood depending from the ceiling. One of the greatest niceties connected with this art is the printing of the sheet on the second side in such a manner that each page, nay, each line, shall fall exactly on the corresponding page and line on the side first printed. To produce this desirable effect, 2 When the sheet is laid on to iron points are fixed in the middle of the sides of the frame of the tympan, which make 2 small holes in the sheet during the first pressure. receive an impression from the second form, these holes are placed on the same points, so as to cause the 2 impressions to correspond. This is termed producing register ; and unless good register is effected, the printing has a very indifferent appearance. However improved, a press of the above description could not impress more than half a sheet; and the practice was to first squeeze so much of the sheet, then relax the handle, wind the second half below the platen, and print it in turn. Thus, each sheet required 4 squeezes to complete it-2 on each side. It is not without a degree of wonder that one reflects on the rudimentary clumsiness of the whole operation; and it seems not less marvelous, that it was by no other process that the best typography could be produced until the conclusion of the 18th c.

The first improvement upon the printing-press was made by the celebrated ear of Stanhope. He constructed the press of iron, and that of a size sufficient to print the whole surface of a sheet, and he applied such a combined action of levers to the screw as to make the pull a great deal less laborious to the pressman, the mechanism altogether being such as to permit much more rapid and efficient working. A multitude of improvements speedily succeeded that of earl Stanhope, in most of which the screw was dismissed, the pressure being generally effected by levers, or by the simple and efficient joint. Among those which have gained a large share of principle of straightening approbation may be mentioned the Columbian press, which is of American invention. This press was brought to Great Britain in 1818 by Mr. George Clymer of Philadelphia, and patented. The pressing power in this instance is procured by a long bar or handle acting upon a combination of exceedingly powerful levers above the platen, the return of the handle or levers being effected by means of counterpoises or weights. For ease and facility of pull, this press is preferred by most workmen; and certainly the powerful

3. Campbell two-revolution PRINTING I.1. Damping machine. 2. Babcock optimus press. 7. Composing stick. 8. Galley. 9. perfecting press. 6. Composition type, cases and rack.

5. Hoe rotary type