“Well, according to my calculations,” said Tom, “we should be about quit of England and striking the Irish Sea at its junction with the Atlantic.  It’s that you believe you see right now.”

“Then before long we’ll glimpse Ireland’s lights!” cried the exultant Jack.  “Though we’re likely to pass over only the city of Cork as we dash on for the big sea beyond.  So far everything is moving like grease, Lieu—­Colin.”

“I promised you it would,” the pilot told him.  “And let’s hope it keeps up this way all the way through.”

Again they ceased trying to talk since it proved such an effort without resorting to the little wireless telephone arrangement.  Jack did notify them, however, when he believed he sighted tiny specks far below that he took for the lights of some place of consequence; but Tom, who knew better, assured him he must be mistaken.

“You’re straining your eyes so much you mistake other things for lights, Jack,” he told the observer.  “It might even be the reflection of the stars on the glasses of your binoculars.  We’re not near Cork yet, and there’s no other place worth mentioning that we’ll come near.  Rest up, Jack.”

“Plenty of time for that after we’ve struck out over the ocean,” came Jack’s defiant answer.

Later on he again declared he saw lights.  They had been speeding for some hours at a rate of more than sixty miles, which was good time for one of those monster heavily laden bombers to make.

“Yes, I imagine it’s Cork this time,” said Tom, when appealed to.  “We veer to the left here, and pass out to sea over Queenstown, don’t we, Colin?”

“According to our mapped-out plan that’s the course,” came the reply, as the pilot shifted his levers, and headed a little more toward the south.

Their sensations at that particular time were very acute.  It was as if they had reached the dividing line, and were about to enter upon a course that would admit of no turning back.

“There, the last glimmer of light has disappeared!” finally cried Jack in an awed tone, “and we’re heading out over the Atlantic, bound for America!”

CHAPTER XVII

WHEN THE SUBMARINE STRUCK

It was long past midnight.

In fact, the aviators could expect to see dawn break before a great while.  When that event came about they knew what an appalling spectacle must greet their wondering eyes.  Above, the boundless expanse of blue sky, with fleecy little white clouds passing here and there, looking like islands in a sea of azure; below, an unending sea of tossing waves, with perhaps not even a fishing vessel in sight.

Jack fell asleep, being utterly tired out.  Tom too caught what he called little “cat-naps” from time to time.  Beverly stuck faithfully to his post, for not a wink of sleep could come to one in whose hands the destinies of the whole expedition lay.