XII 
ARISTARCHUS OF SAMOS 
Historians of mathematics have, as a rule, given too little 
attention to Aristarchus of Samos. The reason is no doubt 
that he was an astronomer, and therefore it might be supposed 
that his work would have no sufficient interest for the mathe 
matician, The Greeks knew better; they called him Aristar 
chus ‘ the mathematician ’, to distinguish him from the host 
of other Aristarchuses; he is also included by Vitruvius 
among the few great men who possessed an equally profound 
knowledge of all branches of science, geometry, astronomy, « 
music, &c. 
‘ Men of this type are rare, men such as were, in times past, 
Aristarchus of Samos, Philolaus and Archytas of Tarentum, 
Apollonius of Perga, Eratosthenes of Cyrene, Archimedes and 
Scopinas of Syracuse, who left to posterity many mechanical 
and gnomonic appliances which they invented and explained 
on mathematical (lit. ‘ numerical ’) principles.’ 1 
That Aristarchus was a very capable geometer is proved by 
his extant work On the sizes and distances of the Sun and 
Moon which will be noticed later in this chapter: in the 
mechanical line he is credited with the discovery of an im 
proved sun-dial, the so-called owa07/, which had, not a plane, 
but a concave hemispherical surface, with a pointer erected 
vertically in the middle throwing shadows and so enabling 
the direction and the height of the sun to be read off by means 
of lines marked on the surface of the hemisphere. He also 
wrote on vision, light and colours. His views on the latter 
subjects were no doubt largely influenced by his master, Strato 
of Lampsacus; thus Strato held that colours were emanations 
from bodies, material molecules, as it were, which imparted to 
the intervening air the same colour as that possessed by the 
body, while Aristarchus said that colours are ‘ shapes or forms 
1 Vitruvius, De architectura, i. 1. 16. 
B 
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