Well might Captain Restronguet exclaim thus, for instead of the protective garb of light absorbing metal the submarine from stem to stern and from the top of the conning-tower to the keel was as black as a lump of coal. CHAPTER XVII. THE RESCUED ITALIANS. As soon as the fore-hatch cover had been unshipped Captain Restronguet, accompanied by Devoran and Kenwyn, hastened on deck. Hythe, hearing the captain’s exclamation, hurried after him. The sky was now perfectly clear, the motion of the sea had almost subsided. But instead of the stinging, ozone-laden breeze a faint odour resembling that of rotten eggs seemed to pervade the air. "H’m," ejaculated Captain Restronguet. "In spite of my faith in the high qualities of restronium the metal has played me false!" "How so, sir?" asked the chief officer. "It is not proof against the action of sulphur. Even now the air reeks of sulphur, and it was a sea highly charged with sulphur that the ’Aphrodite’ passed through when she was in the immediate vicinity of the submarine volcano. Thus the silver in the alloy has been affected, and in place of a light-absorbing metal we have a dead-black surface." "It is a serious look-out, sir," observed the sub. "Serious. Serious isn’t the word for it. We have lost a great factor in our means of offence and defence. We are no longer practically invisible." "Can the defect be remedied?" "Only by subjecting the plating to a fresh treatment, and that can only be done at our base in Sumatra. But be that as it may I mean to continue my search for the ’Vorwartz’. Possibly the margin of superiority lies with her, but, without boasting, I venture to assert that John Restronguet will prove a match for Karl von Harburg. I hope the wireless is intact, Kenwyn?" "It is, sir," replied the second officer. "We have just tapped a message from the P. & O. liner, ’Coghlania,’ seventy miles south of Brindisi." "Anything of importance?" "No, sir; merely on a matter of ordinary routine." "Very good, Mr. Kenwyn. By the by, you might let me know the state of your accumulators. Have we sufficient power to take us to the Ægean?" "I’ll ascertain, sir," replied the second officer.