Page:An introduction to linear drawing.djvu/82

 ﻿point in the horizontal line. From those points where the horizontal lines strike the left hand perpendicular, describe arcs of circles to the base line. From the points where these arcs strike the base line,lead off lines directed towards some one point on the horizontal line, but let them stop at the first vanishing line they strike, and from the point where they strike this vanishing line, draw parallels to the base lines, and by the figure it will be seen that they will strike the other vanishing lines in the points which form the angles of the perspective polygon. Draw lines to these points, and the figure is formed.

fig. 9. plate ii.

To draw the perspective of a house of which one side is parallel to the perspective plane, and in all simi- lar drawings, it is necessary to have the exact measure- ment of every part of the building which is to be rep- resented.

Having drawn the base line C D H and the hori- zontal line A B at the height of a man's head above it, that is, about 5 feet 6 inches, you may fix the centre of the picture at G on the horizontal line. Then raise per- pendiculars on the points C D, equal to the actual height of the building as previously laid down on a proportional scale of parts, and connect these perpendiculars by the horizontal line F E, parallel to the base line. This will complete the/row* of the building, or that part facing the spectator's eye.

To represent the end of the building, draw the van- ishing lines E B and D B. Ascertain the real width of the end, and mark it on the base line, say from D to H. Draw a line from H to the centre of the picture G, and the point where it cuts the vanishing line D B at I is the perspective width of the end. On the point I raise a perpendicular till it strikes the other vanishing