and in refped to any influence upon the train, 'tis in that 
pofitioa (as the Poet fpcaks) Necc^mcqnam nif pond^fs iners, I need 
iiotfpend time to demonftrate this Propofition, confidering 
to whom I write ; and therefore upon the pr fum d concef- 
fion thereof, this confequence muft be allow'd • that if P 
be of a competent weight {I e, not utterly too hghtj to move 
the train at all, it will certainly move it in fome degree of E- 
levation or other in the Quadrant CLT. 
2. If the weight P beconfider'd as to its office of being a 
counterpoife to the body of the movement s as I need 
not prove, that it will perform this no lefs while it hangs by 
upon the VedtsyiV, then if it were faft ri vetted in the fame 
place to the cafe of the Movement : fo I affirm, that in what 
poynt of the Quadrant loever it will move the train, it may 
be alfo a counterpoife to the Body of the Movement. This 
propofition is not altogether fo evident, but moft certainly 
true, as I hope in what follows clearly to demonftrate. Be 
pleas d therefore^ to obferve 
I . That at what poynt foever of the Circle LET QJ^^» 
'the line of Leclivity D E makes an Angle of contadt s on 
the fame poynt will the Diameter S D fall at right angles 
with D E 
2- That the line of dired:ion L D will ever fall upon the 
poynt of Contact D, making an Angle with the Diameter, 
asS D X.. Tliefe x propofitions need no proof 
3 • That the Angle SDL will be always equal to D E H 
? • As great as is the elevation of the line of De- 
cUvity D E above the Horizontal E H Ftg^ 3 fo great will the 
Angle of diftance be between the Diameter S D and the hne 
direction LD Fig^ i. To prove this fee Fig. x, where let 
E H reprefent the Horizon, E D line of dechvity 3 to EH 
draw parallel and to E D parallel h L therefore Angled 
M '^ is equ- to D EH, and e Mb equ. to d Mb ; and becaufe S 
Mh and r M e are right angles, therefore is S M r equal to e M 
and being parallel to L D, the Angle SDL muft be e- 
qualto (SMr,=eMb,=dMh, e. =:toj DE H. and fron^ 
hence it follows. 
4- That the greater the Angle of declivity is in Fig. 3. the 
lefs will the Section LQJD be in Fig. i. and fo on the con- 
trary, the lefs that Angle is, the greater the Section, And 
therefore, 
r The excefs of the weight of L E D above LQD muft 
be alfo greater, by railing up the ftage with the fcrew at S : 
and that excefs lefs, by fcrewingit down. 
6- The lighter that part of the body is, which is repre- 
lented by the Sedion L QJD , the more heavy ought the 
K counter- 
