100 THE BOOK OF THE LANTERN. 



the ground side up, the camera lucida may be used with 

 this as well as with drawing-board, if a piece of white 

 paper be placed beneath it, and the object drawn in the 

 usual way. For outlining and delicate shading I employ 

 H H H H and H H H pencils ; for deep shadows I use 

 H B. By a very delicate employment of the pencil, 

 shadows softer than can be secured by lithography may be 

 made. The camera lucida, of course, is not necessary ; we 

 may draw with the eye and hand alone. If it be necessary 

 to put on colour it may be done cleanly and carefully over 

 the shading ; thus one layer of colour suffices. Now of 

 course, although we have a perfect drawing of the object, 

 with all the detail accurately given, it is not a transparency. 

 But we can easily make it one. Thin some good pale Canada 

 balsam with benzine to about the consistence of cream ; 

 and simply float it over the ground surface of your glass, 

 pour off till the drop comes very sluggishly. Then reverse 

 the glass so that the corner from which the balsam was 

 flowing off be placed upward. Let the return flow reach 

 about the middle, then reverse it again, and move it in 

 several directions to get the balsam level. This may be 

 done with very little practice so that the surface shall be 

 undistinguishable from glass. We have now a perfect 

 transparency. All that is required is twenty -four hours 

 for hardening (keeping the glass level) and then another 

 square of glass fastened on to it by strips of paper at the 

 edges, with small pieces of card at the corners to prevent 

 contact, and it makes an admirable lantern transparency. 



"For obtaining very fine points to my very hard leads, after 

 cutting them very long and even ? and grinding them on 



