n our eyes from the very bosom of those pores, that the smaller
the pores of a body are the more such a body is transparent. Thus paper,
which reflects the light when dry, transmits it when oiled, because the
oil, by filling its pores, makes them much smaller.

It is there that examining the vast porosity of bodies, every particle
having its pores, and every particle of those particles having its own,
he shows we are not certain that there is a cubic inch of solid matter in
the universe, so far are we from conceiving what matter is. Having thus
divided, as it were, light into its elements, and carried the sagacity of
his discoveries so far as to prove the method of distinguishing compound
colours from such as are primitive, he shows that these elementary rays,
separated by the prism, are ranged in their order for no other reason but
because they are refracted in that very order; and it is this property
(unknown till he discovered it) of breaking or splitting in this
proportion; it is this unequal refraction of rays, this power of
refracting the red less than the orange colour, &c., which he calls the
different refrangibility. The most reflexible rays are the most
refrangible, and from hence he evinces that the same power is the cause
both of the reflection and refraction of light.

But all these wonders are merely but the opening of his discoveries. He
found out the secret to see the vibrations or fits of light which come
and go incessantly, and which either transmit light or reflect it,
according to the density of the parts they meet with. He has presumed to
calculate the density of the particles of air necessary between two
glasses, the one flat, the other convex on one side, set one upon the
other, in order to operate such a transmission or reflection, or to form
such and such a colour.

From all these combinations he discovers the proportion in which light
acts on bodies and bodies act on light.

He saw light so perfectly, that he has determined to what degree of
perfection the art of increasing it, and of assisting our eyes by
telescopes, can be carried.

Descartes, from a noble confidence that was very excusable, considering
how strongly he was fired at the first discoveries he made in an art
which he almost first found out; Descartes, I say, hoped to discover in
the stars, by the assistance of telescopes, objects as small as those we
discern upon the earth.

But Sir Isaac has shown that dioptric telesc