As the thing drew nearer to me I could see that it was preceded by a huge curling wave, which was made by some fiendish contrivance to fling itself over the heads and bodies of the three mariners. Every now and then, Gran'pa tugged at a piece of rope astern and the whole craft leapt half out of the water, dived, and then settled down into a sort of erratic seesaw movement. The cliff tops and beach were dotted with excited negroes, and each time Gran'pa pulled the rope they broke into loud cheers and flung themselves about in an ecstasy of wild abandonment. As I watched, I visualized that terrible business of Gran'pa and the dug-out at home in England, and I could see that he was as wilful as ever. To think that I had been working myself to a shadow in this infernal tropical heat while he and Croft and Stringer were disporting themselves in this aquatic and hysterical fashion! I stood up on the boulder top and waved my arms and shouted. The only answer was a loud and unanimous whoop of joy from the negroes, who no doubt thought that I had joined them as another enthusiastic spectator. Presently, however, the craft turned round and began heading in my direction. As it did so, two of the crew were precipitated into the water, where they commenced behaving like hilarious porpoises. The man still left in charge of the thing was (naturally) Gran'pa, who continued serenely onwards until he finally ran aground on a kind of quayside composed of rugged, flat-topped rocks which jutted out into the sea like a pier. It was at this point that I went out to meet him--and tell him exactly what was in my mind. "Come on, George!" he shouted. "Off with your clothes!" The temptation was terrible; but I had to remember my dignity. "I'm ashamed of you!" I said, gazing at his cool, sea-drenched body and laughing face. "What's the matter now?" "I naturally concluded that you were all busy at work--the same as me. How the blazes do you expect us to get this job done if you behave in this demoralizing way?" "Ah! This is a brain-wave. Dr. Croft and I thought it out this morning and acted on it there and then." "So I can gather, quite easily!" Gran'pa turned off the engine and stepped ashore. "Those damned natives are getting sick of work," he said. "This morning they were worse than ever. We offered 'em more cheap and nasty jewelry. But they've lost interest in it. They're overloaded with the stuff. So we cudgelled our brains, and this is the result. At heart they're little children. What they want is enjoyment, not gimcrack knickknacks. This little exhibition of aquatic merriment has turned their heads. Look at them! . . . They'd give anything for a joy-ride on this. See the idea?" "You mean that excursions on this horrible contrivance will be their reward for industry?"