122 LECTURE XI, 



nature, somewhat like a stone maiie. When the drawing is finished, the 

 stone is moistened, and imbibes so much water, that the printing ink will 

 not adhere to it, except at tlie parts where the crayon or the ink has been 

 applied; and in this manner an impression is procured, which has much of 

 the freedom and spirit of an original drawing. When tlie ink is used, a little 

 ' acid is afterwards applied to the stone, in order to corrode its intermediate 

 parts ; and the bold stile of the impression much resembles that of the old 

 wooden cuts. 



The art of printing with separate types was invented soon after the in- 

 troduction of wooden blocks into Europe. Tlie improvement was great and 

 important. The year 144'3, or 1444, is considered as the date of the oldest 

 printed book ; but the precise time and place of the invention remain some- 

 what doubtful: the art, however, advanced towards perfection by very rapid 

 steps. The letters are first cut, in a reversed form, on steel punches; with 

 these a matrix of copper is starhped, and the matrix forms the lower part of 

 the mould in which the types are cast; the metal is a composition of lead 

 and antimony, which is easily fusible. Thus the printed sheet is the 

 fourth form of the letter, reckoning from the original engraving on the punch: 

 in the stereotype printing, lately invented, or rather improved and revived, 

 it is the sixth. In this method, when a form for the side of a sheet has been 

 composed, made up, corrected, and locked up by wedges in the chase or 

 iron frame, which confines it, a mould of the whole is formed in fine plaster, 

 and as many repetitions of it may be cast very thin, in type metal, as will serve 

 to print for the use of a century, without the expense of keeping a large 

 quantity of types made up, or of providing paper for a numerous impression 

 at once. 



The modes of arrajiging the types in boxes or cases, of composing the 

 separate lines on the stick, and making them up by degrees into pages and 

 forms, of correcting the press, of applying the ink, and taking oflf the im- 

 pression, are entirely calculated for the simplicity and convenience of the 

 manual operations concerned, and require little or no detailed explanation.. 



