When every odd piece of paper had been religiously collected and packed in the hamper with the cups and saucers, the little girls were lifted into the boat, Pixie pulled the rudder-ropes over her shoulders, and the Captain pushed the boat from the shore and jumped lightly into his seat. They were off again, rowing homewards and passing once more all the fascinating landmarks which they had noticed on the way down. The picnickers on the banks were fastening hampers and preparing to depart; on the green lawns by the waterside servants were flitting to and fro carrying trays into the house. Inda was beginning to yawn and long for bed. She leant against Pixie, the weight of the small head becoming ever heavier and heavier, but roused up again as the boat entered the "box," as she persisted in calling a lock. She wanted to hand out the parcel of good things without a moment's delay, but the Captain told her to wait until the water had lifted the boat nearer to the bank. It seemed an extraordinary thing that, whereas, in passing through the lock before they had gone down, down, down, they should now rise higher with every moment that passed. The children had a hundred questions to ask, while the Captain stood up and kept the boat in position with a boat-hook. He explained the mystery as simply as possible, and also why he was at such pains to keep at a safe distance from the walls. "You see those things sticking out from the side of the boat into which I put my oars? They are called `rollocks,' and when you are coming up stream through a lock you have to be careful indeed not to let them catch under any of the beams. It would be almost impossible to get them loose again, you see, because every moment more water would pour in, and press them tighter and tighter!" "And what would it do to us if it did press them?" Viva inquired curiously, whereat the Captain smiled and shook his head. "Something very disagreeable, I'm afraid--give us all a good wetting in the water! You needn't be afraid of that, though, when you are with me, for I shall take good care of my little crew. You see how far I keep away with this oar." "Yes, I see. But why does one end of the boat stick out into the middle, and the other into the side?" "It's the current that sweeps it round, the force of the water that is coming in under the gates. That doesn't matter so long as we are not caught." "But the end _is_ caught, isn't it? That little bit of iron that sticks up at the pointed end!" cried Pixie suddenly. She was densely ignorant of all that concerns boats, and invariably alluded to the bow and the stern as the "blunt" and "pointed" ends, to the Captain's intense amusement. This time, however, he did not smile. Pixie saw his face set suddenly as he turned his head to look in the direction of her outstretched finger, but his voice sounded reassuringly confident. "Oh, I see! Yes. Let me pass you, dear, for a moment. Sit quite still!"