72 LECTURE X. 



of points through it, so as to mark the copy, either at once, or by means 

 of charcoal powder ruhbed through the holes, which is called stenciling : 

 and for this purpose, an intermediate copy may be formed on semi-trans- 

 parent paper. Another method is to put a thin paper, rubbed with the 

 powder of black lead or of red chalk, between the original and the paper 

 intended for the copy, and to pass a blunt point over all the lines to be 

 traced, which produces correspondent lines on the paper ; this is called 

 calking. Where the work is large, it may be covered with a thin gauze, 

 and its outlines traced on the gauze with chalk, which is then to be placed 

 on the blank surface, and the chalk shaken off it in the way that a car- 

 penter marks a board with his line/" 



The pen was formerly much used for making rough sketches, and it is 

 still sometimes employed for the same purpose, as weh 1 as for assisting the 

 effect of the pencil. The appearances of uniform lights and shades must 

 necessarily be imitated in drawings with the pen, as well as engravings, by 

 a mixture of the whiteness of the paper with the blackness or colour of 

 the ink, the eye being too remote to distinguish minutely the separate lines 

 by which the effect is produced, although they do not entirely escape its 

 observation. In this respect, drawings in pencils and chalks have an 

 advantage over engravings ; these substances, after being laid on in lines, 

 are spread, by means of rubbers or stumps, of paper, leather, or linen, so 

 as to produce a greater uniformity of tint. Some, indeed, are of opinion 

 that engravings derive a great brilliancy from the hatches that are 

 employed in shading them, and that minute inequalities of colour make 

 every tint more pleasing. In drawings with chalk, however, the advan- 

 tage of rubbers is unquestionable. The lines of a drawing may be made 

 to have an appearance of greater freedom than those of an engraving ; 

 they should be parallel, and when they are crossed [the different sets 

 should be] moderately oblique to each other ; their direction should be 

 governed by that of the outline. Engravings in mezzotinto exhibit no 

 lines : but they are deficient in spirit and precision : the effect of aqua tinta 

 approaches much nearer to that of drawing, and it has a similar advan- 

 tage in the mode of producing its lights and shades. (Plate VI. Fig. 79.) 



It is well known, that the best pencils are made of English black lead, 

 or plumbago. Of black chalks, the Italian is harder and more generally 

 useful than the French : red chalk has the disadvantage of not being 

 easily removed, either by bread or by Indian rubber, without leaving a 

 brownish mark. All these chalks are of the nature of a soft schistus or 

 slate : they may be made to adhere firmly to the paper by dipping the 

 drawings in milk freed from cream, or even in water only, which dissolves 

 the size or gum of the paper. Sometimes a grey paper is used, which 

 serves for a middle tint, and lessens the labour, the lights and shades only 

 being added in white and black chalks. 



Crayons consist of colours mixed up with gum water, or other adhesive 

 substances, and usually also with some chalk, plaster, or pipe clay, so as 

 to be of a proper consistence for working in the manner of chalks. The 



* Imison's Elements, ii. 240, 327. 



