STANHOPE PRESS. 



of the force acting at B, bears a rapidly increasing proportion to 

 the force itself, so that when the levers A c and c G come nearly 

 into a right line, the pressure exerted at B is augmented at G in an 

 almost infinite proportion. 



In working the press, the pressman places a sheet of paper to 

 be printed upon the frame F, called the tympan, where it is held 

 in its place by turning over it the frame G, which is supplied 

 with rods or cords corresponding to the spaces between the pages 

 of the form. While the pressman is thus employed, his assistant 

 is engaged in inking the types with a roller, as shown in fig. 3. 

 When this has been accomplished, the pressman turns down the 

 tympan carrying the paper upon the types, and then, by turning 

 the handle, moves the carriage with the type form upon it under 

 the platten, and applying his hand to the handle above him 

 presses the platten down upon the tympan carrying the paper, and 

 by means of the knee lever produces a sudden and severe pressure 

 by which the paper receives the impression of the type. The 

 handle is then moved in a contrary direction, the platten being 

 raised from the type form, and by turning the other handle the 

 carriage with the type form is removed from under the platten. 

 The pressman then raises the tympan from the types, and taking 

 the printed sheet off, replaces it by a fresh blank sheet, over which 

 he turns the frame as before ; and while he is performing this 

 operation, his assistant is occupied in inking the types, after 

 which the same operations are performed, and another sheet is 

 printed, and so on. 



18. Printing Machines. The printing presses which served 

 the purposes of publication for some hundred years, during which 

 they received no other improvements than such as might be 

 regarded merely as modifications in the detail of their mechanism, 

 have been almost entirely superseded by engines of vastly increased 

 power and improved principles of construction. Although these 

 -admirable machines differ one from another in the details of their 



mechanism, according to the circumstances under which they are 

 applied, and the power they are expected to exert, they are 

 nevertheless characterised by certain common features. 



19. The form to be printed is laid in the usual manner upon a 

 perfectly horizontal table, with the faces of the types uppermost ; 

 and upon the same table, in juxtaposition with the form, and 

 level with the faces of the types, or nearly so, is placed a slab 

 upon which a thin and perfectly regular stratum of printing-ink 

 is diffused ; the table thus carrying the form and inking-slab is 

 moved by proper machinery right and left horizontally, with a 

 reciprocating rectilinear motion through a space a little greater 

 than the length of the form. 



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