Invention Timeline – Alhazen, Arabian Philosopher and Mathematician, First to Correct the Platonic Theory that Rays of Light are Emitted by the Eye
b. ? and d. about 1038
Arabian philosopher and mathematician. He was the first to correct the Platonic theory that rays of light are emitted by the eye. He discovered atmospheric refraction, and what we see the moon after it has set. He was aware that the atmoshere decreased in density with the height, and actually fixed its height at 58 1/2 miles. He showed that weights differed in a rare and a dense atmosphere. He understood center of gravity, and applied it to balances and steelyards. He recognized gravity as a force, though he made it diminish as the distance, and made it purely terrestrial. He had laws of falling bodies, and ideas of capillary attraction. He wrote “Optical Thesaurus,” published in Latin in 1572.
Friend: the Great Ruler, easily content,
Needs not the laws it has laborious been
The task of small professors to invent;
A single wheel impels the whole machine
Matter and spirit; yea, that simple law,
Pervading nature, which our Newton saw.
This taught the spheres, slaves to one golden rein,
Their radiant labyrinths to weave around
Creation’s mighty hearts: this made the chain,
Which into interwoven systems bound
All spirits streaming to the spiritual sun,
As brooks that ever into ocean run.
—Friendship: Schiller
