In [fig. 301] a house is shown in perspective in which the line H L is the line of the horizon and V P is the,—
VANISHING POINT.—The vanishing point is familiarly represented by the rails on a trolley track on a straight road, which seem to approach each other in the distance, as shown in [fig. 302] at V P.
Fig. 302.
All parallel lines seen in perspective appear to meet in the same vanishing point.
The value of the vanishing point may be seen in the view of a wooden house, [fig. 303], where it (V P) gives direction to the retiring lines of the roof, side planks and door.
Fig. 303.
POINT OF SIGHT.—This is that point in the eye where the lines or rays from the object cross each other, as shown at P in [fig. 305], also in [fig. 299] at S.
VERTICAL means perfectly upright. If we attach a piece of thread to a weight, a small piece of lead for example, and hold the thread with the lead hanging downwards, the thread will fall in an upright or vertical position.