PRINTING. 



695 



tanoe, and is called the cap of the press. The 

 cross bar immediately beneath is firmly screwed 

 into the cheeks by mortices, and contains a nut or 

 female screw into which the top of the spindle or 

 upright screw S works. This spindle may be turn- 

 ed round by means of the handle or bar E, and thus 

 rise or fall and carry with it the plattin or flat base 

 which presses the paper on the form of types. 

 At a little distance below the plattin, there is firm- 

 ly fixed in the cheeks the cross piece G, called the 

 winter, and which supports the carriage H, on 

 which the form of types is laid. The carriage may 

 be moved outwards or inwards, on a rail being 

 drawn out, when the paper is to be laid on the form, 

 and moved in when the paper is to be pressed upon 

 the types, by bringing down the plattin. The car- 

 riage is moved out or in by turning a handle be- 

 low called the spit, the motion being communicated 

 through the medium of a wheel and belts. The 

 carriage contains on its upper surface a polished 

 stone or flat piece of iron, called the table, on which 

 the form of types is sustained. At the outer end of 

 the carriage, there is attached an apparatus B F, 

 called the tympan and frisket, the use of which is 

 to fix the paper that it may be brought properly 

 down upon the types. The gallows sustains two 

 parts, i. e. two tympans B, and a frisket F. The 

 tympans are two rectangular thin frames of wood 

 or iron clasped together, and holding a sheet of 

 vellum stretched. The tympans must be large 

 enough to receive the sheet to be printed, which is 

 placed upon it, and fixed upon small projecting 

 points in the sides. The frisket is a rectangular 

 frame jointed to the tympans so as to fold down and 

 inclose the paper. When the paper is adjusted, the 

 frisket is brought down on the tympan, and that 

 closed down upon the types on the carriage; which 

 having been previously inked, the carriage is run in, 

 and the plattin brought down by turning the handle 

 or bar, and thus the impression is obtained. 



The chief ingredients in printers' ink are boiled 

 linseed oil, and some colouring matter, such as lamp 

 black, vermillion, &c. Good ink is absolutely essen- 

 tial to good printing, and no small portion of the 

 beauty of the works printed by our best typogra- 

 phers is attributable to the excellence and durability 

 of the colour of the ink they employed. In the 

 works printed by the Messrs Foulis of Glasgow, 

 the beauty of the ink still remains unimpaired, 

 though their works have been published seventy 

 years since; whereas, in some of the works printed in 

 more recent times, five years are found to make a 

 sensible change in the colour. We do not mean to 

 assert, that the printing ink now generally used is 

 inferior to that in common use formerly ; but we 

 have no hesitation in saying, that, now as formerly, 

 inks of very different qualities have been made and 

 used. 



In former times, the ink was put upon the types 

 by means of two stuffed leather balls, on which some 

 ink was spread, a process which is now abandoned 

 from its extreme tediousness, excepting in the case 

 of very fine work, such as very superior wood cuts, 

 in printing from which a much clearer impression 

 is thus obtained than by inking on the more expe- 

 ditious plan which we are now about to describe. 



Instead of the inking balls, an elastic roller is now 

 in general use. This roller derives its elasticity 

 from a covering of a composition of treacle and 

 glue. The ink is spread upon an iron table, from 

 which a part is taken on to the roller, and spread on 

 the form of types every time the carriage is drawn 

 out As division of labour expedites almost every 

 process of art, so in this it is found advantageous 

 to have two workmen engaged at the same lime 



at one press, the one distributing the ink on the 

 types, while the other is engaged in pulling the im- 

 pressions. 



From the very nature of the mechanical action of 

 the press, Fig. 1. which we have described, it will be 

 seen that great force must be exerted by the work- 

 men, before much pressure can be given by the 

 plattin. and accordingly the working of this press is as 

 laborious an occupation as can be found in any other 

 department of the arts of industry. Of late years, 

 numerous attempts have been made to construct 

 presses adequate to produce a sufficient pressure, and 

 at the same time require less exertion on the part of 

 the pressman. It is a well known law in mechanics, 

 that whatever is gained in power must be lost in 

 velocity; now in the action of the screw press above 

 described, it is manifest that an uniform motion of 

 the bar or handle of the screw will produce an uni- 

 form motion of the plattin, the same exertion being 

 thus made by the workman from the beginning to 

 the end of the pull, whereas the greatest exertion 

 is only required at the end, when the plattin comes 

 down upon the tympan. The most successful at- 

 tempt to improve upon the principle of the old 

 press was made by Mr Roworth, a printer in Lon- 

 don. Instead of the screw at the top of the up- 

 right spindle, he had a projecting bar, which was 

 acted upon by a circular inclined plane fixed in the 

 head of the press, and so formed that when the 

 spindle was turned round by the handle, the inclina- 

 tion of the plane forced the projecting piece at the 

 top downwards, and consequently the plattin ; but 

 the peculiarity consisted in this, that the inclined 

 plane has a greater degree of inclination at the top 

 than at the bottom, and thus the speed of the des- 

 cent at first will be much greater than at the last, 

 and the power being inversely as the speed, it is 

 exerted most where it is most required. 



The advantages of this varied speed of the plat- 

 tin are much more conspicuous in the press of earl 

 Stanhope, represented in Fig. 2., in which A repre- 

 sents the stapple or body of the press, B the stand 

 or bottom piece, called from its form the T. im- 

 mediately above this is the stand or forestay, con- 

 sisting of two parallel rails or grooved ribs, on which 

 the carriage or table D slides in or out from the 

 plattin. H G is a stout lever head fixed into the 

 top of the spindle or screw. E is another strong 

 lever head fixed in an upright arbor, to the lower emi ; 

 of which the handle F is attached. These two lever 

 heads are connected together by a coupling bar or 

 strong rod; thus any motion given to the lever head 

 E produces a corresponding motion in the head G, 

 and thence to the plattin; and the levers are so ar- 

 ranged as to produce the slowest velocity and 

 greatest power at the end of the pull: when the pull 

 has been made, the plattin is raised from the form 

 by the action of a counter weight. The Stanhope 

 press will print a form twice as large as the screw 

 press, with greater ease to the workman. The first 

 press on this construction ever used was completed 

 in the year 1800. 



In the year 1813, the ingenious Mr Ruthven of 

 Edinburgh extended the principle of leverage intro- 

 duced into the Stanhope press, by forming a print- 

 ing-press in which the action of levers was alone 

 employed, without the intervention of the screw ; 

 but the chief merit of his press is its great port- 

 ability. Ruthven's press is represented in Fig. 3. 

 The first peculiarity which must be noticed in this 

 press is, that the table on which the types are 

 placed is stationary, being fixed on the top of the 

 frame of the press, and the plattin above it is 

 moveable on. or off upon rails, in a manner similar 

 to the carriage in the presses formerly described ; 



