2.

Those who write on the science of Geography should trust entirely for the arrangement of the subject they are engaged on to the geometers, who have measured the whole earth; they in their turn to astronomers; and these again to natural philosophers. Now natural philosophy is one of the perfect sciences.704

The “perfect sciences” they define as those which, depending on no external hypothesis, have their origin, and the evidence of their propositions, in themselves. Here are a few of the facts established by natural philosophers.705

The earth and heavens are spheroidal.

The tendency of all bodies having weight, is to a centre.

Further, the earth being spheroidal, and having the same centre as the heavens, is motionless, as well as the axis which passes through both it and the heavens. The heavens turn round both the earth and its axis, from east to west. The fixed stars turn round with it, at the same rate as the whole.706 These fixed stars follow in their course parallel circles; the principal of which are, the equator, the two tropics, and the arctic circles. While the planets, the sun, and the moon, describe certain oblique circles comprehended within the zodiac. Admitting these points in whole or in part, astronomers proceed to treat of other matters, [such as] the motions [of the stars], their revolutions, eclipses, size, relative distance, and a thousand similar particulars. On their side, geometers, when measuring the size of the entire earth, avail themselves of the data furnished by the natural philosopher and astronomer; and the geographer on his part makes use of those of the geometer.