“This is the little devil,” he said, indicating his delicate burden.  “Fulminate of mercury.  This is the stuff that’ll remove your hand with neatness and despatch.  It’s the quickest tempered little article in the business.  Just give it one hard look and it’s off.”

“Here,” said Trendon, “I resign.  From now on I’m a spectator.”

Barnett swung the fulminate in his handkerchief and gave it to a sailor to hold.  The man dandled it like a new-born infant.  Back to his rock went Barnett.  Producing some cord, he let down an end.

“Tie the handkerchief on, and get out of the way,” he directed.

With painful slowness the man carried out the first part of the order; the latter half he obeyed with sprightly alacrity.  Very slowly, very delicately, the expert drew in his dangerous burden.  Once a current of air puffed it against the face of the rock, and the operator’s head was hastily withdrawn.  Nothing happened.  Another minute and he had the tiny shell in hand.  A fuse was fixed in it and it was shoved under the mud-cap.  Barnett stood up.

“Will you kindly order the boat ready, Captain Parkinson?” he called.

The order was given.

“As soon as I light the fuse I will come down and we’ll pull out fifty yards.  Leave the rest of the Joveite where it is.  All ready?  Here goes.”

He touched a match to the fuse.  It caught.  For a moment he watched it.

“Going all right,” he reported, as he struck the water.  “Plenty of time.”

Some seventy yards out they rested on their oars.  They waited.  And waited.  And waited.

“It’s out,” grunted Trendon.

From the face of the cliff puffed a cloud of dust.  A thudding report boomed over the water.  Just a wisp of whitish-grey smoke arose, and beneath it the great rock, with a gapping seam across its top, rolled majestically outward, sending a shower of spray on all sides, and opening to their eager view a black chasm into the heart of the headland.  The experiment had worked out with the accuracy of a geometric problem.

“That’s all, sir,” Barnett reported officially.

“Magic!  Modern magic!” said the captain.  He stared at the open door.  For the moment the object of the undertaking was forgotten in the wonder of its exact accomplishment.

“Darrow’ll think an earthquake’s come after him,” remarked Trendon.

“Give way,” ordered the captain.

The boat grated on the sand.  Captain Parkinson would have entered, but Barnett restrained him.

“It’s best to wait a minute or two,” he advised.  “Occasionally slides follow an explosion tardily, and the gases don’t always dissipate quickly.”

Where they stood they could see but a short way into the cave.  Trendon squatted and funnelled his hands to one eye.

[Illustration:  “Sorry not to have met you at the door,” he said courteously.]

“There’s fire inside,” he said.