MODELLING, PERSPECTIVE, ENGRAVING, PRINTING. 91 



their performance, and perpetuated in their duration, by means of en- 

 graving and printing. If there is any one circumstance to which we can 

 peculiarly attribute the more rapid progress of general civilisation in mo- 

 dern than in ancient times, it is the facility of multiplying copies of literary 

 productions of all kinds, by the assistance of these arts. The distinguishing 

 character of printing consists in the employment of moveable types : the art 

 of engraving is more simple, and in some of its forms more ancient. The 

 Romans were in the habit of using seals and stamps, for marking letters 

 and words oh wax and on pottery; it was usual in the middle ages to 

 employ perforated plates of metal as patterns for guiding a brush, by means 

 of which the capital letters were inserted in some manuscripts, and the 

 Chinese are said to have been long in possession of the art of printing books 

 from wooden blocks.* It was in this form that printing was first intro- 

 duced into Europe, in the beginning of the fifteenth century. There seems 

 to have been formerly a method of engraving on wood with greater ease 

 and accuracy than is now practised ; the hatches may be observed in old 

 wooden cuts to cross each other more frequently and with greater freedom, 

 than in modern works, although some have conjectured, with considerable 

 appearance of probability, that these old engravings were in reality etched 

 in relief on metal. The art of engraving on wood is, however, at present 

 in a high degree of perfection in this country, and blocks are still frequently 

 used for mathematical diagrams and other simple figures : for although 

 they are somewhat more expensive than copper plates, they wear much 

 longer, and they have the advantage of being printed off at the same time 

 with the letter press, and of being included in the same page with the text 

 to which they belong, since the ink is applied to the projecting parts only, 

 both of these cuts and of the common printing types.f 



The method of engraving on plates of pewter or of copper, and of taking 

 impressions, by means of the portion of ink retained in the furrows cut by 

 the graver, was also introduced in the fifteenth century. For dry engraving, 

 the drawing, if it is not executed in black lead, is generally prepared by 

 passing a pencil over its principal features, and the outline is transferred to 

 the plate, which has a thin coat of white wax laid on it, by placing the 

 drawing on it, and rubbing it with a burnisher ; sometimes a drawing in 

 Indian ink, especially if freed from a part of its gum, may be transferred 

 in this manner without the application of a pencil. When written charac- 

 ters are to be engaved, the plate is laid on a cushion, so as to be readily 

 turned under the graver, which is a great convenience in forming curved 

 lines. 



In laying on equable shades of considerable extent, much labour is saved 

 by the use of a ruling machine, which enables us to draw lines, at any re- 

 quired distance, very accurately parallel, and either straight, or following 

 each other's gentle undulations, in order to avoid Jhe appearance of stiffness. 



, * Du Halde, Description de 1'Empire de la Chine, 4to, 1736. Zani, Material! 

 per Servire alia Storia dell' Incisione in Rame ein Legno, Parma, 1802. 



f An account of the re-discovery of the mode of decarbonizing steel so as to ren- 

 der it capable of being engraved on, will be found in the Tr. of the Soc. of Arts, 

 vol. xli. 



