" a triangle is a three-sided **rectilineal** figure."

A triangle is a **rectilineal** figure; i.e.

Quadrilaterals, hexagons, &c., all of which are **rectilineal** figures, a triangle is "differentiated" as having three sides.

Since the area of a circle equals that of the **rectilineal** triangle whose base has the same length as the circumference and whose altitude equals the radius (Archimedes, KIKXou A ir, prop.i), it follows that, if a straight line could be drawn equal in length to the circumference, the required square could be found by an ordinary Euclidean construction; also, it is evident that, conversely, if a square equal in area to the circle could be obtained it would be possible to draw a straight line equal to the circumference.

Wood potentially a table; primary, as an indeterminate something which is a substratum capable of becoming natural substances, of which it is always one; and it is primarily the matter of earth, water, air, fire, the four simple bodies (airxa 6w,uara) with natural **rectilineal** motions in the terrestrial world (De Gen.

Aristotle could not know enough, physically, about Nature to understand its matter, or its motions, or its forces; and consequently he fell into the error of supposing a primary matter with four contrary primary qualities, hot and cold, dry and moist, forming by their combinations four simple bodies, earth, water, air and fire, with natural **rectilineal** motions to or from the centre of the earth; to which he added a quintessence of ether composing the stars, with a natural circular motion round the earth.