REMARKS TO THE STUDENT 



XXIX 



The rough ends thus formed make an excellent "stump" for rubbing 

 shaded areas. However, practice is necessary to avoid smudging. 



Fig. 7. — Preliminary stage in the making of the drawing shown in Fig. 8. 



The procedure in constructing a finished laboratory drawing may 

 now be explained. Suppose you are studying the external structure of 

 a young salamander and wish to represent what you have observed 



