The gentlemans recreation in two parts : the first being an encyclopedy of the arts and sciences ... the second part treats of horsmanship, hawking, hunting, fowling, fishing, and agriculture : with a short treatise of cock-fighting ... : all which are collected from the most authentick authors, and the many gross errors therein corrected, with great enlargements ... : and for the better explanation thereof, great variety of useful sculptures, as nets, traps, engines, &c. are added for the taking of beasts, fowl and fish : not hitherto published by any : the whole illustrated with about an hundred ornamental and useful sculptures engraven in copper, relating to the several subjects.

Of the Subject to be seen.

THe Base of any thing is the Plain, Flat, or Floor, upon which any solid Body or Ob∣ject [ 60] is placed, or raised.

The Altitude is the Perpendicular space of place, betwixt the Base and the Eye, or height of the Visual Point above the Base. The Visual Point is a Point in the Horizontal Line, wherein all the Beams of the Eyes Unite. The Horizon∣tal Line is a Line that proceeds from the Center of the Eye, to the Visual Point, parallel to the Horizon of the Earth.

The Distance is the space on the Base, between the Glass and Point in the Base, that lies directly under the Eyes.

The Section is a Plain of Transparent matter (as of Glass) raised upright upon the Plain of the Base standing before you, parallel to a strait Line, passing through the Convex Centers of both Eyes. Now without the understanding of this Section or Glass, tis impossible to attain to the Knowledge of Perspective, and by Consequence will not be able to give a reason for the difference betwixt the Orthographick, and Scenographick Figures.

If the Glass is placed near the Visual Point, and remote from the Object, the Figure which is seen will be very small; because all Rays comprehending the Orthographical, and Scenographical, Figures fall in∣to the Visual Point, as their Common Center. If the Visual Point be more raised (though at the same Distance) the Scenographick Figure or Form will appear much larger. And by reason the Visu∣al Radiations are higher, the various Perpendicu∣lars raised on the Section, or Glass, cut them in wider distances, as being more remote from the Glass. If the Glass incline to the Visual Point, the Scenographick Vision will be longwise between the Visual Point and the Object; But if the Glass recline from the Visual Point, the Scenographick Figure will appear rounder, and begin to resem∣ble the Orthographick. But if the Glass is fixed Equidistant to the Base, or Plain the Object stands upon, the Scenographick and Orthographick resemblance will be one and the same.

Diagonals, or Lines of Distance, are such as are drawn from the Point of Distance, to any other Point higher, or lower than the Horizon.

The Object is that Form, Body, Figure, or Building intended to be expressed in Perspective Proportions.