פירוש על ברכות 53:11

They understood "morning by morning" to mean half the morning was for gathering the manna ; and since they consider the morning to be from 6 a.m. to noon, this would mean in the first three hours and the other half would be for melting.

They gathered the manna within the four hours, but they anticipated the commencement by one hour, thus finishing in the third hour of the day.