THE PRINTING PRESS. 



2. Printing, in its most general sense, is the name given to all 

 processes in the arts, by which the same forms or characters are 

 indefinitely multiplied, by the impressions of the surface upon 

 which they are formed repeatedly and successively, upon the 

 surface to which they are to be transferred. Thus, in calico- 

 printing, the same figures are transferred in rapid succession to 

 different pieces of cloth, or to different parts of the same piece, by 

 means of blocks or rollers, upon which, the figures are produced, 

 either in relief or intaglio, that is, either in raised or sunken 

 characters. In such cases the blocks, or rollers, are pressed in 

 succession on the surface of the cloth to be printed, being however 

 previously smeared with colouring matter. In the printing of 

 copper or steel engravings, the design is produced by the engraver 

 in lines sunk in the surface of the copper or steel by the engraving 

 tool. These lines being filled with the printing-ink, and all 

 other parts being carefully cleaned, the plate is impressed on the 

 paper with an intense pressure by means of a press specially 

 adapted to that purpose. The paper being previously moistened, 

 absorbs the ink from the lines in which it is deposited, and 

 exhibits after the impression a perfect copy of the engraving, 

 the sunken lines of the engraving being represented on the paper 

 by corresponding lines in ink. 



3. In wood- engravings, and in ordinary book- printing, the 

 original from which the impressions are taken is in relief. A 

 model in relief of the page to be printed is formed in metal called 

 type-metal, consisting of lead rendered hard by being alloyed 

 with a small proportion of antimony. The surface being smeared 

 with the colouring-matter called printing-ink, is impressed upon 

 the paper, and ufac-simile of the original relief is thus produced. 



4. In the earliest and rudest attempts at printing, a manu- 

 script page was attached to the surface of a block of wood, 

 which was carved into relief corresponding with the characters, 

 of the manuscript. The impression produced by this means was 

 necessarily a fac-simile, more or less accurate, of the manuscript 

 itself. 



5. The method of printing by means of blocks of wood, or 

 metal, carved in relief, is the earliest example on record of the 

 practical use of the art which, in its more improved state, has 

 exercised so important an influence upon civilisation. According 

 to some antiquarian authorities, the art of producing characters in 

 this way may be traced as far back as the building of Babylon. 

 The characters found upon bricks, taken from the supposed site of 

 that city, having been undoubtedly printed by the method here 

 described. "We are in possession of metal stamps, with words 

 engraved in relief, which the Romans made use of to mark their 



