Sir Isaac Newton’s BookIII.

dy may be made of any propofed degree of fmallnefs. Butthe folid matter of a body fo framed will take up only halfthe fpace occupied by the body; and if each conftituentparticle be compofed of other lefs particles according tothe fame rule, the folid parts of fuch a body will be but afourth part of its bulk ; if every one of thefe leffer parti-cles again be compounded in the fome manner, the folidparts of the whole body fhall be but one eighth of its bulk;and thus by continuing the compofition the folid parts ofthe body may be made to bear as fmall a proportion to thewhole magnitude of the body, as fhall be defired, notwith-ftanding the body will be by the contiguity of its parts ca-pable of being in any degree hard. Which fhews that thiswhole globe of earth, nay all the known bodies in the u-niverfe together, as far as we know, may be compoundedof no greater a portion of folid matter, than might be re-duced into a globe of one inch only in diameter, or evenlefs. We fee therefore how by this means bodies may ea-fily be made rare enough to tranfmit light, with all thatfreedom pellucid bodies are found to do. Though whatis the real ftru&ure of bodies we yet know not.

Chap. IIL

Of the Refraction, Reflection,and Inflection of Light.

i

T HUS much of the colours of natural bodies; ourmethod now leads* us to {peculations yet greater, no

lefs