THE ART OF DRAWING. 137 
&e., called the plane of the picture; secondly, any more or less colored 
substance, as, for instance, lead-pencil, chalk, Indian ink, common ink, &c. 
By means of the latter we make on the former either mere lines, answer- 
ing to the outlines of the body to be represented, the aggregate of which is 
called the contour; or we draw also within the contour various degrees of 
shades, corresponding with the light and shade of the body, which is called 
the shading. The shading is performed in several manners, from which 
the work is denominated a drawing in hatching, in graining, in Indian 
mk, &e. | 
A more essential difference of the graphic manner arises from the prin- 
ciple which governs it. If the graphic representation of an object is founded. 
upon optical laws, ¢. e. upon the real perception of an object from one 
point in space, it is then called a natural drawing of the object; for such. 
a drawing, in being looked at from a proper position and distance, strikes 
the eye in the same way as the object itself viewed from the same point. 
Such a natural drawing is also called a perspective drawing or a perspective 
projection, from the optical laws applied in its construction, in opposition 
to the geometrical projection of the same object, made on geometrical laws, 
which are reducible to an imaginary perception from an infinite distance, 
by means of parallel rays of sight. Natural drawing alone belongs to the 
Fine Arts. In closely comparing the appearance of an object in a natural 
drawing with its real configuration, we readily perceive that it essentially 
differs from a geometrical projection of the same; that the former is but 
an optical phenomenon representing the image of the object in the same 
way as it falls, through the pupil, upon the retina of the eye. 
It follows from what has just been said that the conditions required for 
producing a natural drawing are: 1. The exact knowledge of the real shape 
of the object; 2. The knowledge and application of its optical appearance 
upon a plane. The former is taught by J/orphology or the doctrine of 
Forms, the latter by the Art of Perspective. The two combined are the 
basis of the art of drawing; while the doctrine of illumination (of shades 
and shadows) teaches the distribution of the degrees of light on and around 
the object. 
A. Morphology, or Doctrine of Forms. 
The objects of the art of drawing are the visible bodies and phenomena 
of nature and of social life. It is the duty of the artist to render himself 
capable of representing them with exactness in a natural drawing. He 
must, therefore, study those portions of architecture, of botany, zoology, of 
the theory of clouds and of the movements of water, which treat in general 
of the forms of their objects. He must, moreover, endeavor to find in 
nature a certain model for each single object which he is about to draw, 
with the view of practising its several parts in preparatory essays, and 
of developing on it the peculiar individual character which he intends 
representing in his drawing. Such extensive preparatory studies cannot 
be enjoined upon a mere amateur of the art. Yet even he ought never to 
draw anything, or even copy any drawing, for which he cannot procure 
521 
