The Project Gutenberg eBook, Treatise on Light, by Christiaan Huygens,
Translated by Silvanus P. Thompson

This eBook is for the use of anyone anywhere at no cost and with
almost no restrictions whatsoever. You may copy it, give it away or
re-use it under the terms of the Project Gutenberg License included
with this eBook or online at www.gutenberg.net

Title: Treatise on Light

Author: Christiaan Huygens

Release Date: January 18, 2005 [eBook #14725]

Language: English

Character set encoding: ISO-646-US (US-ASCII)

***START OF THE PROJECT GUTENBERG EBOOK TREATISE ON LIGHT***

E-text prepared by Clare Boothby, Stephen Schulze, and the Project
Gutenberg Online Distributed Proofreading Team

Note: Project Gutenberg also has an HTML version of this
file which includes the original illustrations.
See 14725-h.htm or 14725-h.zip:
(http://www.gutenberg.net/dirs/1/4/7/2/14725/14725-h/14725-h.htm)
or
(http://www.gutenberg.net/dirs/1/4/7/2/14725/14725-h.zip)

TREATISE ON LIGHT

In which are explained
The causes of that which occurs
In REFLEXION, & in REFRACTION

And particularly
In the strange REFRACTION
OF ICELAND CRYSTAL

by

CHRISTIAAN HUYGENS

Rendered into English by

SILVANUS P. THOMPSON

University of Chicago Press

PREFACE

I wrote this Treatise during my sojourn in France twelve years ago,
and I communicated it in the year 1678 to the learned persons who then
composed the Royal Academy of Science, to the membership of which the
King had done me the honour of calling, me. Several of that body who
are still alive will remember having been present when I read it, and
above the rest those amongst them who applied themselves particularly
to the study of Mathematics; of whom I cannot cite more than the
celebrated gentlemen Cassini, Roemer, and De la Hire. And, although I
have since corrected and changed some parts, the copies which I had
made of it at that time may serve for proof that I have yet added
nothing to it save some conjectures touching the formation of Iceland
Crystal, and a novel observation on the refraction of Rock Crystal. I
have desired to relate these particulars to make known how long I have
meditated the things which now I publish, and not for the purpose of
detracting from the merit of those who, without having seen anything
that I have written, may be found to have treated of like matters: as
has in fact