“I don’t know, sir.”

“Ah, yes, I remember; you were asleep at your post. Well, I’m happy to inform you that the number I saw placed in the river was exactly twenty-seven. Now, Mr. Telegrapher, stand up here and make yourself useful. If explosions occur, no man is to speak, but each is to keep count of the number of spurts of water he sees, then we will compare notes at the end of the fusillade.”

“By Jove!” exclaimed the doctor, his eyes glued to the telescope.

A tall pillar of water, white as snow, rose into the air, paused, broke like a sky-rocket, and subsided in a misty rain, which the wind caught and blew along the surface of the water. Then three more shot up into the air as if in competition. A sound like distant thunder came across the delta, and now it seemed that one mine had set off another, or else the logs were even thicker than might have been expected, for a wall of water rose from the surface of the river, extending, with breaks here and there, from shore to shore, and instead of a rumble, a sharp thunderclap was heard by the four men on the mountain. This made counting impossible. For a few moments nothing further happened, then a quarter of a mile down the river the line of mines went off practically simultaneously, forming for a brief instant a Niagara in the sky.

“I think we’ve got them,” said Stranleigh quietly, as he slung over his shoulder again the binoculars he had been using. “Turn your telescope to the land again, doctor, and see those comical people tumbling over each other in their haste to find out what has happened. They look like a nest of disturbed ants.”

“What have you done with the yacht?” asked Mackeller. “If any of those people have seen sawn logs float down the river there will be an investigation very speedily to discover who has done the sawing.”

“That is true, Mackeller. I have therefore taken the yacht across the river out of gunshot, or the sight of our abandoned Utopia. If they come by land they can’t reach her.”

“They are not coming by land,” said the doctor. “The steam launch is being got ready, and three men are standing on the rock ledge preparing to go aboard, I fancy. They are armed with rifles, too.”

“Just glance through the telescope, Mackeller,” said Stranleigh, “and tell me if you recognize the three men.”

“Yes; there is the tall manager, with the captain of the Rajah on one side of him, and the first mate on the other.”