6o2 THE POPULAR SCIENCE MONTHLY. 



used on wood, excepting the heavier wood scaupers, as they are 

 called (chisels or gouges would perhaps give a better idea of 

 what they are). These could not be used on steel, because the 

 hand of the artist could not force them through the line to be 

 cut; so a more delicate graver is used, and a great many cuts 

 are taken in the same line, thus making it broader and deeper 

 by degrees. 



There are several kinds of picture engraving and etching, the 

 most prominent of which are aquatint, mezzotint, stipple, roulet- 

 ting, and line engraving. 



Aquatint is a kind of etching used to get the effect of draw- 

 ings in India ink, and at one time it was greatly made use of in 

 rendering the drawings of Paul Sandby and our early water-color 

 painters, and particularly prints for drawing-books. 



There are many ways of preparing a plate for this work, but 

 the following is the best : Have three different solutions of rosin 

 in rectified alcohol, making them of various degrees of strength, 

 but always thin enough to be quite fluid, the weakest solution 

 being almost colorless. First pour the strongest solution on the 

 plate, which has previously been very carefully cleansed from all 

 oil and grease that would prevent the acid acting upon the steel. 

 When this strongest solution dries it produces a granulation, and 

 you may now bite or corrode the steel with acid through these 

 granulations for your darker tones, stopping out with a varnish 

 made of sealing-wax dissolved in alcohol where the acid is not to 

 operate, or the acid may be applied with a brush where the dark 

 tones are desired. After cleaning the plate as before you proceed 

 with the weaker solutions in the same way ; the weakest giving 

 the finest granulations for skies, distances, etc. 



The process requires a good deal of stopping out and some 

 burnishing and scraping for the high lights in finishing. 



Another style of aquatinting is done by placing a clean plate 

 in an air-tight box where there has been a dust of rosin circulated 

 by means of a bellows attached to the box. The finest of the par- 

 ticles of rosin are allowed to settle on the plate, which is then 

 heated until this dust of rosin sticks to it where it has fallen. 

 The acid is now put to work as before. This gives an even tint 

 something like the other ])rocess, the difference being in this cae 

 that the acid bites the plate between the particles of rosin, mak- 

 ing a black around a white, whereas in the first process the acid 

 acts through the granulated rosin, producing a black surrounded 

 by a white. An impression of either of these plates, taken in ih.e 

 condition the acid leaves them, would resemble a tint or wash of 

 color on paper. 



David Allan engraved his celebrated illustrations of the Gen- 

 tle Shepherd in this manner. This style of engraving has now 



