The three officers were standing on the after deck of the "Aphrodite." The submarine had again risen to the surface and was plugging away in a southerly direction on her vague quest for the unbeatable "Vorwartz." Captain Restronguet remained below, absorbed in some abstruse problem.
The sea was smooth, but dark clouds, edged with bright, copper-tinted hues, were rapidly banking up against the westerly breeze, while the rumble of distant thunder was heard at frequent intervals. Even though it was close on midday the sun's light was greatly obscured; while, on the other hand, the far away Sudan coast stood up clearly under the effect of atmospheric refraction.
There was every indication of a sharp yet severe storm.
"Are you going to submerge her, Devoran?" asked the sub.
"Not on my own responsibility," replied the chief officer. "Until the captain gives the order--ah, here he is."
"I cannot understand how the detector is acting," said Captain Restronguet, as he gained the group of officers. "I have most carefully tested the currents and examined the platinum contact breakers. The instrument seems in order, yet it records nothing of the presence of the 'Vorwartz.' It is inexplicable."
"The 'Vorwartz' is doubtless beyond the field of electrical action, sir," remarked Kenwyn.
"So I have been told before," replied Captain Restronguet with asperity. "All the same that theory will not hold good. We ought to have had an intimation of that craft's presence when she torpedoed the 'Noord Brabant.' How can you explain that?"
"Don't you think, sir, we ought to submerge the ship?" asked Devoran, anxious to change the subject. "The glass is falling----"
"There is plenty of time," declared the captain, who was evidently not in his usual easy-going humour. "It certainly looks threatening, but at this moment the sea is as calm as glass. Look at those sharks, Devoran. Vicious looking brutes, aren't they? Suppose we give the men an opportunity at rifle practice."