140 THE EARLIEST GREEK GEOMETRY. THALES 
a mathematician; but whether he contributed anything to 
geometry as such is uncertain. True, Suidas says that lie 
‘ introduced the gnomon and generally set forth a sketch 
or outline of geometry ’ (oAcoy yecopeTpias vnoTvircoaLv eSeL^eu) ; 
but it may be that ‘ geometry ’ is here used in its literal sense 
of earth-measurement, and that the reference is only to the 
famous map. 
‘ Next to Thales, Ameristus, a brother of the poet Stesichorus, 
is mentioned as having engaged in the study of geometry; 
and from what Hippias of Elis says it appears that he acquired 
a reputation for geometry.’ 1 
Stesichorus the poet lived about (530-550 b. C. The brother 
therefore would probably be nearly contemporary with Thales. 
We know nothing of him except from the passage of Proclus, 
and even his name is uncertain. In Friedlein’s edition of 
Proclus it is given as Mamercus, after a later hand in cod. 
Monac. 427; Suidas has it as Mamertinus (s.v. Stesichorus); 
Heiberg in his edition of Heron’s Definitions, writes Mamertius, 
noting Mappenos as the reading of Cod. Paris. Gr. 2385. 
1 Proclus on Each I, p. 65. 11-15.