Opticks 1717 - Up

377 -j
,as generalLaWs 0 ature, by which the Things
thcmfelvcs are form’d : their Truth appearing
to us by Phenomena $ though their Caufes be
not yet difcover’d. For ‘thef’e are manifeit Qua..
lities, and their Caufes only are occult. And
the xf$otelians gave the Name of ‘occult Qua..
Iities not to lnanifefi ()xhties, but to fueh
Qualities only as they fuppofed to lie hid in
Bodies, and ro be the unknown Ca~zh of manifeit
k%e(Ps: Such as would be the Caufes of
Gravity, and o E magnetick and ele&riclr A.
traktions Y and of Fermentations, if we fhOd
firppofe that thefe Forces or ACtions arofe fixxrt
Qualities unknown to us, and uncapable of being
dikovered and made manifek Such oci=ult
Qualities put a itop to the Iniprovetnen~
of natural Philofophv, and thcrcfore of late
years have been reje&ed. To tell us thi~t
every Species of Things is cndow’d with an oc-,
cult ‘i‘pccificl;Quality by which it a&s and produces
rnanifeit EffccCts; is to tcI1 us nothing:
But to derive two or three general Principles
of Motion from Phenomena, and afterwards
to tell us 110~7 the Properties and A&ions of all
corporeal Things follow from thofe mnnifel~
Prillciples, would be a VefY gK3t ib2p ill .I%-
~o~~pl~~~, th0ugh the Cd& of thofe Principles
’ brere not yet difccnrer’d : And therefore 1, kCcrLl-
pie’ llot to p~op0i-c the Principies of MOtlQIl 3-
[love ‘~cntion’d, they being of very general Extent,
qnd leave their Cauks to be found out.
Now by the help of thefe Principles, a11 maprial
Things ftxm to have been coqofed of
. the