C 3 
fecht towards a (Fig. 3.) fo that th:e S|)lierulcs, iike 
A and B-, (Fig. 7.) touch beyond the Spring will 
break : Likewife if the Spring be bent the other way, 
till the Spherules touch beyond g, then it will break 
the other way. Now when the Spherules touch at 
or at g, g, the Spring is as likely to return to its 
firft Pofition as to break 5 for which Reafon I have 
call’d the Points e a'nd 'g, Boints of Equilibrium ^ as 
alfo having known by Experience, that a Spring left 
bent to a certain Degree, has, after fome time, broke 
of itfelf. 
From all this it appears, that Spherical t’artides 
will never make a tough Spring j therefore the Fi- 
gure of the Particles miift be alter’d, in order to render 
it ufcful; and this is what is done in bringing down 
the Temper of the hard Steel, and letting d 
Springy as it is call’d. What Change ought to be 
made iil the Particles, lhall firft fhew j and then 
confider how far that is dohe by thofe who make 
Springs. 
If the Parts fuppos’d Globules, as in Fig. 3. are now 
flatten’d at c, where the Contafl is, fo as to put on 
the Shape ne dc S^€Sy {zs in Fig. 8.) the Contact will 
be much increas’d, and reach from d to cT, fO that 
in bending the Spring there will ftill remain a great 
COntafl in the Particles, and the Points of 
briiim for breaking {viz. Oy e above, and g, g below) 
Will be remov’d nearer to the Poles H, or j, thari 
when the F^articles are round 5 the Confcquence of 
which will be, that the Spring muft be bent much 
farther, to be in Danger of breaking, than in the 
fbrrner Suppofition j as may be fecn in Fig. 0. where 
two Particles being open’d about the Point ^ as a 
' A a Centre, 
