### Full text

An ESSAY
for then, what is on the Right, will appear on

the Left.

Therefore, I lay my Perſpective Plane upon

the Geometrical Plane; ſo that it be between

the Horizontal Plane, and the Figures requir’d

to be thrown into Perſpective.

## 27. Problem I.

22. To find the Appearance of a Point, which is in

the Geometrical Plane.

Let Z be the Geometrical Plane, I E the Baſe

Line, D V the Horizontal Line, V the Point

of Sight, D one of the Points of Diſtance, and

A the given Point.

### 27.1.

## 28. Operation .

From the Point A, let fall the Perpendicular

A B upon the Baſe Line; and from the Point of

Concurrence B, draw the Line B V to the Point

of Sight; then aſſume B E in the Baſe Line

equal to B A, and from the Point E draw the

Line E D to the Point of Diſtance D: And the

Point (a), the Interſection of B V and E D, is

the Repreſentation ſought.

## 29. Demonstration .

23. The Appearance of the Line A B, is a Part
of the Line B V. Now, if we conceive a Line

iſſuing from the Eye towards the Point D, and

another from the Point A towards the Point E; theſe two Lines will be parallel, becauſe they

are in parallel Planes, aud each make half a

right Angle with the Perſpective Plane; whence