GRAPHICS. 167 
secured in a wooden handle. The gravers are ground off obliquely at the 
point, and the face is either low, 2. e. forms a square (jigs. 25a and 25 d), 
or high, 2. e. lozenge-shaped (fig. 240); there are also knife-gravers 
(jigs. 26), whose face forms a very acute-angled triangle. The low-faced 
_graver is used for tracing out the design, the high-faced for deepening the 
strokes, and the knife-graver for fine, very sharp lines. The beard or burr 
that forms on the edge of the stroke is removed with the scraper (figs. 14 
and 15), which serves also to scrape out slight faults; and any roughness 
that may be produced in consequence is rnbbed down with the burnisher 
(jig. 16)..The graver lies while at work almost flat on the plate; the 
manner of holding it is shown in jigs. 7 and 8. For very broad lines 
gravers are used with faces formed as in jigs. 26a and 266. During 
the process of engraving the plate lies either on a sand-bag (engrav- 
ing-cushion) or on a desk-shaped easel (jig. 7 a), and in executing 
curved lines it is turned round with the left hand. In order to examine 
portions of his work as they are executed, the artist rubs them over with 
the otl-rubber (fig. 9), which consists of a ball of felt rolled tightly together, 
on which there is some lamp-black moistened with oil. If any mistakes 
are made which are too deep to be effaced by the scraper, they must be 
knocked up. This is done from the back; the plate is laid on a small anvil — 
(jig. 31), and the knocking up is done either with the hammer (jig. 32) 
alone, or, if the places are very small, with a punch (jigs. 29 and 30), 
which is placed upon the faulty spot and struck with the hammer. The 
back of the spot to be effaced is found by means of the callipers (jig. 27) 
or of the improved compasses (jigs. 28a and 286). Straight lines are 
drawn with the ruler (fig. 12) and parallels with the parallel ruler (fig. 18); 
but such surfaces and tints as are formed wholly of parallel lines are now 
almost always ruled with the machine. The laying down of curved lines is 
a chief object of care with the artist, who must lay them according to the 
rules of perspective in order to represent the roundings of the forms. For 
this purpose the apparatus represented in pl. 22, jig. 35, is of use, where 
the shadows cast by the threads of the frame upon the bust indicate the 
correct perspective curve of the strokes to be used in delineating it. 
In the second mode of engraving, with the dry-point, the strokes are cut 
through the ground with steel needles of various shapes, and frequently 
these strokes run cross-wise over each other. This mode of engraving 
demands great certainty in the artist, and then it furnishes very fine and 
delicate work, which, however, will seldom bear more than 200 impressions. 
The third mode of engraving, that of etching, is entirely different from the 
preceding. Here the ground is not removed when the outline is done, but 
the whgle drawing with all its shades, &c., is completed in it. For this 
purpose variously shaped etching-needles of hardened steel (jigs. 20, 21, 22) 
are employed, which are handled like lead-pencils, excepting that each 
stroke must pierce through the ground so as to lay the plate bare. When 
the drawing has been gone over in this manner, the artist proceeds to biting 
am. The etching-liquor consists of nitric acid diluted with rain-water. For this 
purpose the plate is surrounded by a border of yellow wax, which is smeared 
551 
