TO-DAY everyone in the least interested in archæology has heard of the Sumerian culture of Mesopotamia and the cuneiform system of writing that was developed there. Not everyone realizes that only so recently as 1850 was the existence of this all-important non-Indo-European and non-Semitic people so much as suspected. Nowadays, of course, the Sumerians take pride of place as the dominant cultural element in Mesopotamia from the fourth to nearly the beginning of the second millennium B.C., and the influence of their culture is known to have spread far and wide and to have lasted long after the folk themselves had been swamped by their Semitic neighbours. Why are there to-day sixty seconds in a minute, sixty minutes in an hour, and 6 × 60 degrees in a circle? Because the Sumerians used a unit of sixty. Their unit of weight, the mina, seems to have been just about equal to the Imperial pound.