the radius. His speculations as to the ether, his suggestive views of
the structure of crystalline bodies, and his explanation of opacity,
slight as they are, will possibly surprise the reader by their seeming
modernness. And none can read his investigation of the phenomena found
in Iceland spar without marvelling at his insight and sagacity.
S.P.T.
June, 1912.
TABLE OF MATTERS
Contained in this Treatise
CHAPTER I.
On Rays Propagated in Straight Lines.
That Light is produced by a certain movement.
That no substance passes from the luminous object to the eyes.
That Light spreads spherically, almost as Sound does.
Whether Light takes time to spread.
Experience seeming to prove that it passes instantaneously.
Experience proving that it takes time.
How much its speed is greater than that of Sound.
In what the emission of Light differs from that of Sound.
That it is not the same medium which serves for Light and Sound.
How Sound is propagated.
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