[The following Communication was made to the Society by 
the President, S. De Witt, Esquire, and may be found 
in his treatise on Perspective, lately published.] 
Drawing in Perspective Mechanically . 
A.DAMS, in his Geometrical and Graphical Essays , justly 
observes, that “ there is no artist who will be hardy enough 
to say that he can delineate by the eye the same object 
“ twice with exactness, and preserve a just and similar pro- 
“ portion of parts in each. In one of the figures we shall 
“ find some of the parts larger than in the other ; both can- 
d not be right; yet supposing them perfectly the same, 
“ neither may be conformable to nature. Add to this, many 
« situations of an object occur, which no eye, however ha- 
« bituated, can represent with accuracy.” 
This difficulty of making true representations of objects 
by drawing by the eye , has given rise to a number of con¬ 
trivances to effect the same purpose with greater exactness 
and ease. Among these, one of the simplest is to make a 
frame in the shape of a parallelogram and divide the space 
inclosed by it into small squares, by stretching threads 
across it; and to divide the paper, on which the drawing is 
to be made, with pencil lines, into similar squares, num¬ 
bering the ranges of squares on the frame and those on the. 
paper in the same manner. The frame is then set up per¬ 
pendicular, between the eye and the objects, with a fixed 
sight at some distance before it through which the objects 
are observed, and what is seen through any square of the 
frame is drawn on the corresponding square on the paper; 
this being done through all the squares will give a repre¬ 
sentation on the paper, corresponding, in all its proportions, 
to the objects intended to be drawn. 
In order to acquire an expertness in this manner of draw¬ 
ing, it will be of use for the learner to exercise himself in 
