The Flood Waters Receding One Cubit Every Four Days in Av

"Until the tenth month" — this was Av, which was the tenth from the descent of the rains. "In the tenth month, on the first of the month, the tops of the mountains were seen" — the high ones, upon which the waters had been fifteen cubits. From the day the waters began to go and diminish, there were sixty days. It is found that the waters that were upon the tops of the mountains diminished, every four days, one cubit of the waters.