Like the measurements of Aristarchus and Eratosthenes, this calculation of alhazen is simple enough in theory.
The original investigations of alhazen had to do largely with optics.
A later edition was published, together with a translation of alhazen, by F. Risner in 1572.
In the meantime the law of reflexion had been discovered; that for refraction foiled alhazen, and was reserved for a European.
alhazen's explanation of the use of the retina and lens was adopted.
alhazen discovered atmospheric refraction, and showed that we see the sun and the moon after they have set.
The determinations of the densities- of bodies, as given by alhazen, approach very closely to our own. '
Pre-eminent among Arabian scientists is alhazen, who flourished in the 11th century.
alhazen gave the correct explanation, which, however, Friar Bacon attributes to Ptolemy.
In the field of physical science one of the most important of the Arabian scientists was alhazen.