That was the first exact hour’s practising that ever any little girl did by any sort of clock. “Ribbon-fish mine,” said the Prehistoric Man to his wife, when Vertebrata had finished, “I have been thinking additional thoughts. Why could we not use the circle in other ways?” “What ways, besides for your coming home and for Vertebrata’s practising?” asked the Prehistoric Woman; but we must forgive her for knowing about only those two things, for she was a very Prehistoric Woman indeed. “Little bones might be laid between the big bones,” said the Man--and by that of course he meant measuring off minutes. “By certain of them you could roast flesh and not kneel continually beside the fire. By certain of them you could boil eggs, make meet the cakes, and not be in peril of burning the beans. Also....” He was silent for a moment, looking away over the soft breast of the wood where the sun was shining its utmost, because it has so many reasons. “When I look at that moving finger on the circle thing,” he said slowly, “it feels as if whoever made the sun were saying things to me, but with no words. For his sun moves, and the finger on the circle thing moves with it--as if it were telling us how long to do this thing, and how long to do that thing--you and me and Vertebrata. And we must use every space between the bones--and whoever made the sun is telling us this, but with no words.” The Prehistoric Woman looked up at her husband wonderfully. “You are a great man, Troglodyte!” she told him. At which he went away to hunt, feeling for the first time in his prehistoric life as if there were a big reason, somewhere out in the air, why he should get as much done as he could. And the Prehistoric Woman went at her baking and cave-tidying, but always she ran to the door of the cave to look at the circle thing, as if it bore a great message for her to make haste, a message with no words. As for Vertebrata, she had taken her pipes and danced away where, on rocks in the landscape, the other little Prehistorics sat about, getting their practising done. She tried to tell them all about the circle thing, waving her pipes and jumping up and down to make them understand, and drawing circles and trying to play to them about it on her pipes; and at last they understood a little, like understanding a new game, and they joined her and piped on their rocks all over the green, green place. And the Seconds and Minutes and Hours, being fairly started to be measured, all came trooping on, to the sound of the children’s piping. When the sun was at the top of the sky, Vertebrata remembered, and she stuck a stick in the ground and saw that there was almost no shadow. So she left the other children and ran very hard toward her own cave. And when she had nearly reached it, somebody overtook her, also running very hard. [Illustration: SAT ON A ROCK IN THE LANDSCAPE AND PRACTISED.]