DRAWING. 



any practical utility. The pupil should familiarise 

 himself with the various different appearances 



Fig. 1 6. 



which a single object, as a box or a book, may be 

 made to assume by being placed in different 

 positions. 



The relation between a perspective drawing 

 and the perspective appearance of nature, may be 



Fig. 17. 



simply illustrated by placing a piece of slightly 

 smoked glass in a vertical position ; and with the 

 eye kept strictly at the same point, by tracing, 

 with the aid of any fine-pointed instrument, the 

 outline of objects seen beyond, the result will be 

 a correct perspective picture. If the tracing thus 

 made be held in an angular position in reference 

 to the eye, it will have a distorted effect ; or if 

 placed parallel to the spectator, but removed 

 above, below, or aside from the eye, it will be 

 impossible to see it correctly. In proportion as it 

 is placed in its original position in reference to the 

 eye, it will seem to become more true ; but only 

 when placed exactly in the same position as 

 when the tracing was made, does it appear per- 

 fectly correct. 



And so with all drawings there is only one 

 point from which they can appear with correct- 

 ness ; this is called the point of sight or point of 

 view. It is that from which the drawing is made, 

 and from which it should be viewed when finished. 



To make use of the point of sight in perspective 

 drawings, it is transferred to the plane of the 

 picture in the following manner : Having decided 

 or ascertained the distance of the eye from the 

 drawing equal to from one to one and a half 

 times the width of the drawing, as the case 

 may be draw the horizontal line HH (fig. 18), 

 where the horizon of the scene should occur. 

 Mark the point on it immediately opposite the 

 eye, and draw a vertical line, PE, equal to the 

 distance ; its extremity, E, will be the eye or point 

 of sight transferred to the plane of the picture. 



As a general rule, the angle produced at the 

 point of sight by the lines coming trom the bounds 

 of the picture on the horizontal line, as H, E, should 

 be equal to the number of degrees on the horizon 



contained in the picture. The horizon is divided 

 into 360 degrees, and supposing the picture to 

 include sixty of these, or one-sixth of the visible 

 horizon, it would be necessary that the point of 

 ~ight should be so far from the principal point, that 



the angle formed there by the lines H, E, would 

 contain the same number of degrees. 



The point P has been erroneously termed the 

 point of sight. The old masters termed it the 

 centre, because the eye naturally chooses the point 

 of sight opposite the centre in looking at a picture. 

 However, as it is not absolutely necessary that it 

 should be exactly so, the best modern authors 

 term it the principal point. 



It is optional to transfer the point of sight either 

 above or below the horizontal line. In fig. 18, it 

 is represented below. The choice of either posi- 

 tion depends on convenience, or on the nature of 

 the subject 



To draw Circles in Perspective. The most 

 convenient way for amateur practice is to lot a 

 square, by dividing its sides into any convenient 

 number of equal parts, as in 

 fig. 19. This might be done 

 on card-board, and kept by 

 itself, to refer to when re- 

 quired. Then, by placing a 

 square in the picture in the 

 position of the circle re- 

 quired to be drawn perspec- 

 tively, and lotting it, as in 

 fig. 20, we proceed to note 

 carefully where, in fig. 19, 

 the circle comes in con- 



Fig. 19. 



tact with the lines ; and touching these points 

 with the pencil, we draw the circle as seen in per- 

 spective A map, or picture on a wall, may be 

 represented perspectively in the same manner. 



This is also a very good way to draw pointed 

 Gothic windows, ellipses, or other figures : indeed, 

 by having recourse to this very simple expedient, 

 the artist might insure sufficient accuracy in the 

 perspective representation of any object whatever ; 



