SCIENTIFIC DRAWING AND DESCRIPTION 69 



talents of individuals should receive the greatest 

 encouragement and stimulation, and if some can 

 accurately shade so as to make their diagram a good 

 picture, so much the better. But at first the drawings 

 must be, above everything, clear accurate diagrams of 

 the actual structure. . To this end every line and spot 

 in them should represent something in the object, and 

 no spot nor line allowed to the equivalent of which 

 in the object the student cannot point. Moreover, 

 outlines should be complete, and no loose ends, nor 

 hazy joinings, nor dim angles, should be permitted. 

 Such imperfections generally correspond to loose, hazy, 

 or dim ideas, which it is one of the chief uses of the 

 drawing to remove and to replace by clear and sharp 

 conceptions. It is for this reason the generalized dia- 

 grams, to be spoken of later, are of such great value. 

 I have found that "rough drawings," sometimes recom- 

 mended, are of very little use, and the impressionist 

 kinds, often really beautiful, made under teachers 

 untrained in scientific methods, are little better. The 

 true diagrammatic drawing takes but little if any more 

 time, and is many times more valuable. Indeed, a 

 mere " drawing ' of an object, i.e. a representation 

 of its appearance to the eye, a reproduction of the 

 impression the object makes upon the beholder, has 

 very little if any scientific value in connection with 

 laboratory work, and is not worth the time it takes. 

 Such drawings are in place in a drawing class, and 



