[ 49 1 
the Refinance of the Spring, and the Force p, exactly 
counterbalancing one another j then the Force zp will 
bend the Springthro’ the Space ofT wo Inches, 3 p thro’ 
Three Inches, 4 p thro’ Four Inches, &c. the Space 
Cl [Fig. 2.), thro’ which the Spring is bent, or by 
which the End C is removed from its natural Situ- 
ation, being always proportional to the Force which 
will bend it fo far, and will detain it fo bent. 
And if one End L be fattened to an immoveable 
Support, Ftg. 3. and the other End C be drawn out- 
wards to /, and be there detained from returning 
back by any Force p , the Space Cl, thro’ which it 
is fo drawn outwards, will be always proportional to 
the Force p, which is able to detain it in that Situ- 
ation. 
And the fame Principle holds in all Cafes, where 
the Spring is of any Form'whatfoever, and is, in any 
Manner whatfoever, forcibly removed from its na- 
ural Situation. 
Here, Sir, I prefume, you will think it material 
to take notice, that the claftic Force of the Air is a 
Power of a different Nature, and governed by dif- 
ferent Laws, from that of a Spring. For fuppofing 
the Line LC , Fig 1. to reprefent a cylindrical Vo- 
lume of Air, which, by Comprellion, is reduced to 
LI, Fig. 2. or, by dilatation, is extended to L L 
Fig. 3 - its elaftic Force will be reciprocally as A/, 
Fig 2 and 3 ; whereas the Force or Refinance of a 
Spring will be dirc&ly as Cl. 
I now proceed to my general Propofition, and its Co 
rollaries j in which if Ifhall happen at any time toex- 
prefs myfelfwithlefs Accuracy, as in making Weights, 
G Times, 
