1

them. From the things premiſed I gather that the project ſwiftly

ſwinged round by the projicient, in its ſeparating from it, doth

tain an impetus of continuing its motion by the right line, which

toucheth the circle deſcribed by the motion of the projicient in

the point of ſeparation, by which motion the project goeth

tinually receding from the centre of the circle deſcribed by the

motion of the projicient.

them. From the things premiſed I gather that the project ſwiftly

ſwinged round by the projicient, in its ſeparating from it, doth

tain an impetus of continuing its motion by the right line, which

toucheth the circle deſcribed by the motion of the projicient in

the point of ſeparation, by which motion the project goeth

tinually receding from the centre of the circle deſcribed by the

motion of the projicient.

The project

veth by the

gent of the circle of

the motion

dent in the point of

ſeparation.

veth by the

gent of the circle of

the motion

dent in the point of

ſeparation.

SALV. You know then by this time the reaſon why grave

dies ſticking to the rim of a wheele, ſwiftly moved, are extruded

and thrown beyond the circumference to yet a farther diſtance

from the centre.

dies ſticking to the rim of a wheele, ſwiftly moved, are extruded

and thrown beyond the circumference to yet a farther diſtance

from the centre.

SIMP. I think I underſtand this very well; but this new

ledg rather increaſeth than leſſeneth my incredulity that the Earth

can turn round with ſo great velocity, without extruding up into

the sky, ſtones, animals, &c.

ledg rather increaſeth than leſſeneth my incredulity that the Earth

can turn round with ſo great velocity, without extruding up into

the sky, ſtones, animals, &c.

SALV. In the ſame manner that you have underſtood all this,

you ſhall, nay you do underſtand the reſt: and with recollecting

your ſelf, you may remember the ſame without the help of

thers: but that we may loſe no time, I will help your memory

therein. You do already know of your ſelf, that the circular

tion of the projicient impreſſeth on the project an impetus of

ving (when they come to ſeparate) by the right Tangent, the

circle of the motion in the point of ſeparation, and continuing

long by the ſame the motion ever goeth receding farther and

ther from the projicient: and you have ſaid, that the project

would continue to move along by that right line, if there were not

by its proper weight an inclination of deſcent added unto it; from

which the incurvation of the line of motion is derived. It ſeems

moreover that you knew of your ſelf, that this incurvation

ways bended towards the centre of the Earth, for thither do all

grave bodies tend. Now I proceed a little farther, and ask you,

ther the moveable after its ſeparation, in continuing the right

tion goeth always equally receding from the centre, or if you will,

from the circumference of that circle, of which the precedent

tion was a part; which is as much as to ſay, Whether a moveable,

that forſaking the point of a Tangent, and moving along by the

ſaid Tangent, doth equally recede from the point of contact, and

from the circumference of the circle?

you ſhall, nay you do underſtand the reſt: and with recollecting

your ſelf, you may remember the ſame without the help of

thers: but that we may loſe no time, I will help your memory

therein. You do already know of your ſelf, that the circular

tion of the projicient impreſſeth on the project an impetus of

ving (when they come to ſeparate) by the right Tangent, the

circle of the motion in the point of ſeparation, and continuing

long by the ſame the motion ever goeth receding farther and

ther from the projicient: and you have ſaid, that the project

would continue to move along by that right line, if there were not

by its proper weight an inclination of deſcent added unto it; from

which the incurvation of the line of motion is derived. It ſeems

moreover that you knew of your ſelf, that this incurvation

ways bended towards the centre of the Earth, for thither do all

grave bodies tend. Now I proceed a little farther, and ask you,

ther the moveable after its ſeparation, in continuing the right

tion goeth always equally receding from the centre, or if you will,

from the circumference of that circle, of which the precedent

tion was a part; which is as much as to ſay, Whether a moveable,

that forſaking the point of a Tangent, and moving along by the

ſaid Tangent, doth equally recede from the point of contact, and

from the circumference of the circle?

SIMP. No, Sir: for the Tangent near to the point of contact,

recedeth very little from the circumference, wherewith it keepeth

a very narrow angle, but in its going farther and farther

off, the diſtance always encreaſeth with a greater proportion; ſo

that in a circle that ſhould have v. g. ten yards of diameter, a point

of the Tangent that was diſtant from the contact but two palms,

would be three or four times as far diſtant from the circumference

recedeth very little from the circumference, wherewith it keepeth

a very narrow angle, but in its going farther and farther

off, the diſtance always encreaſeth with a greater proportion; ſo

that in a circle that ſhould have v. g. ten yards of diameter, a point

of the Tangent that was diſtant from the contact but two palms,

would be three or four times as far diſtant from the circumference