Opticks 1717 - Up

P
&$OLV if this Tabie be compared with the 6th -
Scheme, YOU Will there fee the conititution of
ea~:h CO~OW, as to its IngredieCts, or the original
CoJours of which it is compounded, and
fknce be enabled to judge of its Tntenfenefs or
Imperfe&ion ; \vl:ich may SMice in explication
of the 4th and 18th Obfcrvatians, unlefs it be
farther defired to delineate the manner how
the Cdours appear, \vhen the two ObjeCt-gIai”-
ks arc laid upon one another. To do which,
kt there be defkibed a large Arc of a Circle,
and a &eight Line which may touch that Arc,
and parallel to that. Tangent feveral occult
Lines, at iilch .diftanccs from it, as the Numbers
fet againfl: the feveral Colours in the Ta-
He denote. Fsr the Arc, and itsTangent; will
reprefent the Snperficies of the CMk tcrminating
the interjaccnt Air ; and the places wlierc
the occult Lines cut the Arc will ihow at what
diitanccs from the center, or Point of conta&,
each Colour is reMIted.
There are aI.fo other UfG of thisTable: For
by its afifiance the tbicknefs of the Babble in
the i 9 th Obfervation was deteimin’d by the Co-
Iours which it exhibited. And fo the bignefs
of the parts of natural Bodies may be conje- ”
&ured by their Colqurs, as $111 be hereafter
fllewn. Alfo, if two or more very thin Pli~teS
be laid one upon ‘another, ib as to compofe one
IDlate equalling them all in thiclinefs, the refiilt-
+ Colour may be hereby determia’d. Far inf~al~ce,
Mr. heroic! obi’eryed, as is mentioned in
his ik/lz’cmgl~qQhik , -that a fain.t yellow Plate of
&$ufcovy C;kafs laid upon a blue one, conflituted