In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. And the rain was upon the earth forty days and forty nights. The great Biblical flood so described in Genesis has long been a subject of fascination and speculation. In the 19th century the English archbishop James Ussher established it as having happened...