“A shark for a shilling,” he cried, “and a big one too. You see if he doesn’t hang about the sloop and show himself in the morning, turning up his eyes on the lookout for whoever it was that tried to poison him.”

“Turning up his eyes!” said Murray. “Nonsense! If it was as you say the shark would be turning up its white underparts and floating wrong way up.”

“Maybe; but hold hard a minute; it’s rather soon to exhibit the other dose, as old Reston calls it. I’m not going to make an exhibition of myself, though, this time, so here goes. You see if Jack Shark doesn’t go for the bottle as soon as I throw it overboard. Here goes!” Splash!

“How stupid!” said Roberts. “I ought to have drawn the cork.”

“Oh no,” said Murray, laughing. “I don’t suppose the directions said, to be taken in water.”

“Um—no. But what’s to be done? Look; he’s got it.”

For as the descent of the bottle Roberts had thrown in could be traced by the way in which the tiny phosphorescent creatures were disturbed, lower and lower through the deep water, there was another vivid flash made by some big fish as it gave a tremendous flourish with its tail, and the midshipman rubbed his hands with delight.

“He’s got it, I’m sure,” he cried. “But what’s to be done? No use to pitch in a corkscrew.”

“Not a bit, Dick,” replied Murray cheerily.

“What a pity! I ought to have known better. He’s got it, but the glass will stop the draught from having the proper effect.”