The reasons for the base 60 , or sexagesimal, system are now lost in the mists of time.
Boyer suggests that one possible reason may have been that so many different
subdivisions are possible with 60 as a base: “it has been suggested that astronomical
considerations may have been instrumental... it appears more likely, however, that
the base sixty was consciously adopted and legalized in the interests of metrology, for
a magnitude of sixty units can be subdivided easily into halves, thirds, fourths, fifths,
sixths, tenths, twelfths, fifteenths, twentieths, and thirtieths, thus affording ten possible
subdivisions” (Boyer 1991 : 25 ). Not all scholars agree. Powell hypothesized that the
sexagesimal system was “an ethno-linguistic phenomenon and nota mathematical crea-
tion” (Powell 1976 : 418 ). He noted that the Sumerian language contains “sexagesimal
number words. The reasons why their language used this counting structure are
inadequately known and cannot be reconstructed with certainty” (Powell 1976 : 418 ).
–– Tonia Sharlach ––Figure 15.1 HSS 3. 35. An Early Dynastic
tablet from Girsu (courtesy of the
Semitic Museum, Harvard University)