they had kept track of the days, checking each one off on their calendars, but the calendars had long since been mingled indistinguishably with the stuff of the planet itself—along with most of the rest of their equipment. By that time, however, they had learned that the cycle of wet and dry seasons was almost precisely equivalent to a pair of their own Terran years, so they had no more need for the calendars. But at the beginning of this wet season Carnahan had begun marking off the days once again with scratches on the post of the hut in which he lived. The chronometers were gone, too, but one and three-quarters Earth days equalled one Serrengian day, and by that he could compute when the ships from Earth were due.