['8j3 
or Oil, orGreafc. Another way of making Springs, 
is to begin and fhape them in cold unclaftic Steel, 
and then having heated them to a fmall Degree, for 
Example, to a Blood red Heat, immediately to cool 
them in fome proper Liquors. This alfo fettles the 
Particles in their oblong Figure, through which they 
muft pafs before they become round, or nearly fo, in 
a white Heat. That Particles of Steel are fix’d in the 
Figures which they have at the Inftant of dipping, 
will not appear ftrange, when we confider, that dip- 
ping red-hot Steel in cold Liquors, in a particular 
Pofition, makes it magnetical. If it be ask’d. How we 
account for making Springs only with hammering, 
it is eafily anfwer’d. That we can make Iron and Steel 
magnetical only with hammering ; and if we can 
give and deftroy Poles in the whole Piece, there is 
no Improbability to think we can give Poles to little 
Parts} or rather bring into a particular Situation the 
Poles which they have } for if the Poles that we have 
confider’d be plac’d quite irregularly, there will be no 
Elafticity at all. Agreeable to this. Springs may be 
made of other Metals than Iron or Steel, though not 
fo perfeft, by Hammering } for it will be fufficient for 
the little Particles to have Poles that attract and repel 
one another, driven by the Hammering into a regular 
Order. 
N. B. Th 'tSi apply d to the Vibration of a String, 
will better folve its fever al Cafes than AttraBion 
alone', and the Elafticity of Glafs is juft the fame as 
that of a very brittle Steel-Spring, 
A a a 
VII. Some 
