"Look!" said Tilda, pointing to a distant ripple drawn straight across the surface. "There goes a rat, and I've won!" The boy said-- "A boat takes up room in the water, doesn't it?" "0' course it does. But what's that got to do with rats?" "Nothing. I was thinking of Sam's puzzle, and I've guessed it. A boat going downwards through a lock would want a lock full, all but the water it pushes out from the room it takes up. Wouldn't it?" "I s'pose so," said Tilda doubtfully. "But a boat going up will want a lock full, and that water too. And that's why an empty boat going downhill takes more water than a loaded one, and less going up." To Tilda the puzzle remained a puzzle. "It _sounds_ all right," she allowed. "But what makes you so clever about boats?" "I've _got_ to know about them. Else how shall we ever find the Island?" She thought for half a minute. "You're sure about that Island?" she asked, a trifle anxiously. Arthur Miles turned to her with a confident smile. "Of course I'm sure." "Well, we'll arsk about it when we get to Stratford-on-Avon." She was about to say more, but checked herself at sight of a barge coming down the canal--slowly, and as yet so far away that the tramp of the tow-horse's hoofs on the path was scarcely audible. She laid a hand on 'Dolph's collar and pressed him down in the long grass, commanding him to be quiet, whilst she and the boy wriggled away towards an alder bush that stood a furlong back from the bank. Stretched at length behind the bush, she had, between the fork of its stem, a clear view of the approaching boat. Its well coverings were loose, and by the upper lock gate the steersman laid it close along shore and put out a gang-plank. His mate, after fitting a nosebag on the horse, came at a call to assist him, and together they lifted out a painted wooden steed wrapped in straw, and carried it to the store. Having deposited it there, they returned and unloaded another. Five horses they disembarked and housed thus; and then, like men relieved of a job, spat on their hands and turned to work their boat down through the locks. For twenty minutes the children lay prone and watched them, Tilda still keeping a hand on the scruff of 'Dolph's neck. Then, as the boat, having gained a clear reach of water, faded down in the gathering dusk, she arose and stretched herself. "For anyone but Bill I wouldn' risk it," she said. "But maybe his credit depends on gettin' them 'osses delivered to-night." She took Arthur Miles by the hand, found the road, and dragged him uphill at a trot towards the group of red brick buildings that showed between the trees. The buildings consisted of a cottage and a long stable or coach-house contiguous. This presented a blank white-washed wall to the road, but a Gloire de Dijon rose spread itself over the cottage front, almost smothering a board with the inscription: _S. Holly and Son, Carters and Hauliers_.