380 PERSPECTIVE. 



point G, towards which they tend, is the centre of 

 the picture. 



Oblique perspective is when the plane of the pic- 

 ture is supposed to stand oblique to the sides of 

 the objects represented ; in which case the repre- 

 sentations of the lines upon those sides will not be 

 parallel among themselves, but will tend towards 

 their vanishing point. This kind of perspective is 

 shown in Plate 7. Fig. 1. 



A bird's-eye view is a view supposed to be taken 

 in the air, looking down upon the object j and 

 differs from the usual way of drawing perspective 

 views, only in supposing the horizontal line to be 

 raised much higher. 



When an object is to be drawn in perspective, 

 all its parts must be measured, so that we may be 

 able to lay them down from a scale of equal parts. 

 Having determined whether it is to be parallel 

 or oblique perspective, the first thing to be drawn 

 is the horizontal line, which is to be put parallel to 

 the bottom of the drawing, and as high above it 

 as the height of a man's head, as H G, Plate 6. 

 Fig. 1., which is five feet six inches above the bot- 

 tom of the house. Next determine on the centre 

 of the picture G, which must be placed so as to 

 leave convenient room for the representation. Fix 

 on C the nearest corner of the object, and draw the 

 perpendicular C B : lay off C D equal to the length 

 of the building, and draw D A and A B. From C, 

 the nearest corner, draw C G, to the centre of the 

 picture. C G now contains the line which repre- 

 sents the bottom of the end of the house ; but this 

 is an indefinite representation, of which we do not 

 yet know the exact length. The method of deter- 

 mining this is as follows : Continue the line DC to I, 



