"Mr. Webb!" called out Captain M'Bride, seeing the Sub approach.
Webb hurried up to the captain and saluted.
"Better? That's good," said the skipper. "Look here, muster a party and start digging a trench on the left of that wall of thorn bushes. Bring it at a sharp angle to the shore. Three feet deep will be enough, if you pile the displaced sand on the outside edge of the trench."
The young officer soon found half a dozen men who had figured on his watch bill. These, provided with the broken blades of oars, which formed excellent spades for throwing out soft sand, set strenuously to work despite the heat of the day.
"Strikes me there's somethink precious hard, sir," remarked an able-seaman after the party had been at work for twenty minutes. "Rock or somethink."
"Sandstone, possibly," replied the Sub. "No matter, you're nearly down to the required depth." The man plied his wooden spade vigorously in order to lay bare the supposed rock. Suddenly he gave an exclamation of astonishment.
"Blow me!" he exclaimed, "a bloomin' petrol tin."
With a strenuous heave he wrenched the can from its hiding-place. As he did so the sides of two adjacent tins were revealed.
"We've found what I believe to be a secret petrol store, sir," reported Webb to his skipper.
"Eh, what?" exclaimed Captain M'Bride, hurrying towards the partly excavated trench. "By Jove, Mr. Webb, it looks like it! Start one of those metal caps and see if the can really contains petrol."