_Of Light. It’s proportional quantities on the different Planets. It’s
Refractions in Water and Air. The Atmosphere; it’s weight and
properties. The Horizontal Moon._
[Sidenote: The amazing smallness of the particles of light.]
165. Light consists of exceeding small particles of matter
issuing from a luminous body; as from a lighted candle such
particles of matter continually flow in all directions. Dr.
NIEWENTYT[34] computes, that in one second of time there flows
418,660,000,000,000,000,000,000,000,000,000,000,000,000,000 particles of
light out of a burning candle; which number contains at least
6,337,242,000,000 times the number of grains of sand in the whole Earth;
supposing 100 grains of sand to be equal in length to an inch, and
consequently, every cubic inch of the Earth to contain one million of
such grains.
[Sidenote: The dreadful effects that would ensue from their being
larger.]
166. These amazingly small particles, by striking upon our eyes, excite
in our minds the idea of light: and, if they were so large as the
smallest particles of matter discernible by our best microscopes,
instead of being serviceable to us, they would soon deprive us of sight
by the force arising from their immense velocity, which is above 164
thousand miles every second[35], or 1,230,000 times swifter than the
motion of a cannon bullet. And therefore, if the particles of light were
so large, that a million of them were equal in bulk to an ordinary grain
of land, we durst no more open our eyes to the light than suffer sand to
be shot point blank against them.
[Sidenote: How objects become visible to us.