"Then you would organise a service of fast turbine steamers running all over the canal systems of the country?" "Exactly. Or let us say--er--launches," said Dubberley. "I must not overstate my case." "Travelling twenty miles an hour?" "Say fifteen, sir," said Dubberley magnanimously. "Mr Dubberley," said Robin, in a voice which made us all jump, "have you a bathroom in your house?" Even the Twins, who were growing a trifle lethargic under the technicalities of the subject, roused themselves at this fresh turn of the conversation. "Ah--eh--I beg your pardon?" said Dubberley, a trifle disconcerted. "A bathroom," repeated Robin--"with a good long bath in it?" "Er--yes." "Well, Mr Dubberley, when you go home this afternoon, go upstairs and fill the bath with water. Then take a large bath-sponge--something nearly as broad as the bath--and sweep it along from end to end, about a foot below the surface, at a speed of fifteen miles per hour--that will be twenty-two feet per second--and see what happens!" Robin had unconsciously dropped into what I may call his debating-society manner. His chin stuck out, and his large chest heaved, and he scooped the air, as if it had been the water of Dubberley's bath, with one of Kitty's priceless Worcester teacups. Dubberley sat completely demoralised, palpitating like a stranded frog. "Then," continued Robin, "you would observe the result of placing a partly submerged and rapidly moving body in a shallow and restricted waterway. You would kick half the water right out of the canal to begin with, and the other half would pile itself up into a wave under your bow big enough to offer an almost immovable resistance to the progress of your vessel." He leaned back and surveyed the bemused Dubberley with complete and obvious satisfaction. We all sat round breathless, feeling much as Sidney Smith must have felt when some one spoke disrespectfully of the Equator. Great was the fall of Dubberley. He moved, perhaps instinctively, in a society where he was seldom contradicted and never argued with. One does not argue with a gramophone. And here this raw Scottish youth, with the awful thoroughness and relentless common-sense of his race, had taken the very words out of his mouth, torn them to shreds, and thrust them down his throat. I am afraid I chuckled. The Twins sat hand in hand, with dreamy eyes staring straight before them. They were conjuring up a joyous vision of Dubberley, in his shirt-sleeves, meekly refuting one of his own theories by means of a childish and sloppy experiment in practical hydrodynamics in his own bathroom.