four o'clock
Of course it was useless thinking of having anything hot while going along at even half speed , much as they would have enjoyed a cup of coffee to warm them up , for the rain and fog made the air seem chilly . `` But in a race every minute ought to count , '' remarked Jack , when Jimmie suggested this thing of stopping half an hour . `` This is our running time , you know . After four o'clock we can hold up all we want . In fact we have to , as nothing gained by keeping on then counts . '' And so they ate a cold `` snack , '' as Jack called it , while pursuing their course down the river . Jimmie was again perched in the bow , talking when his jaws were not otherwise taken up in masticating his sandwich .