through the conning tower hatch of the submarine emerged a sailor, holding high a brilliant flare that looked like a small searchlight.

“what’s your number, lads?” he hailed.

“four of us, sir,” weakly responded jimmy.

the sailor stepped out on the slippery deck of the boat, that alternately rose and fell in the swell of the sea.

“whereaway?” questioned the sailor.

“to the bottom of the sea, if you don’t give us a lift,” replied jimmy.

the sailor turned to the hatch, sent a call below, and two more jaunty tars sprang through the opening.

one of the last comers was just a youngster in years, but evidently qualified for his dangerous calling.

“by the ghost of bloomsbury park,” he exclaimed, when extending a helping hand to jimmy, and when the latter’s face showed in the shine of the flare, “if it isn’t stetson!”

“i’ll be blowed if it isn’t ned!” jimmy had joined familiar company, it seemed.

[153]

“seven hands ’round, jimmy,” cried the young sailor, “did you drop from the clouds?”

“no,” said jimmy, wringing the water from his cap, “i came by the boiler route to help celebrate your birthday.”

in the meantime, jimmy’s fellow swimmers had been assisted to the deck, and were practicing again the art of drawing a long breath.

all of the wet ones had begun to shiver, for the wind had a sharp edge to it.

“bring them below”—this command from the conning tower, by a fourth sailor, who appeared to speak with authority.

glad of the chance to get under cover, the chilly explosion survivors followed the officer below the hatch, and immensely enjoyed the warmth of the snug quarters.

“you’ll find this isn’t much of a passenger boat, my lads; it fits too tight to suit most people.” this remark from the officer showing the way.

“it felt mighty good to us when we couldn’t find the bottom of the sea with our feet.”

billy’s happy disposition was again working.

it was jimmy’s hour, this business of being inside of a submarine. our aviator boys might be princes of the air, but down here jimmy stetson was the ace, and all the other cards. he could not give henri any points that would puzzle about the gasoline engine that furnished the power when[154] the craft was running on the surface, and, perhaps, not a great deal that was new about the electric motor that propelled the boat when under the water, but to all of the visiting boys, except jimmy, there was much of mystery about the way the vessel was raised and lowered.

how, when the ballast tanks are full, they sink the hull of the submarine until only the periscope and top of the conning tower are visible, and, when empty, the whole of the conning tower, superstructure, and a portion of the hull ride above the water.

how hydroplanes—short, broad fins—tilt the nose of the vessel so that the propeller can drive the craft down fifty or sixty feet.

jimmy knew all about it, and the sailors let him have all the pleasure of telling it to his wondering companions.

the guarded screw propeller aft and outside, the vertical steering rudders behind it, the air flasks which supply the crew with air when the vessel is submerged, the torpedo equipment—all the details thereof were reeled off by the dover boy with great gusto.

ned belton, with whom jimmy had trained for submarine service in london, laughingly nominated his friend, there and then, for head talker on a sight-seeing ’bus.

with roving commission, the submarine was lazily[155] drifting, half submerged, within sight of the lighthouse with the famous hexagonal tower, near nieuport-bains, a little seaside resort in belgium.

the boys had realized that it was considerable of a cramp for the submarine to carry passengers in the limited space allotted to the crew, and barring this extreme emergency, it would not have done at all for this fighting machine to serve any other than the purpose intended.

it was agreed that the submarine would go as far as dunkirk, in the hope that opportunity would there present itself for the passengers to pursue the returning course in some other vessel.

a surprise beyond any dream of great fortune awaited them at dunkirk.

this port just then was a working out point for aircraft for scout duty on the north sea.

from the conning tower of the submarine henri and billy were watching with keen interest the a?rial maneuvers then in progress. suddenly the lighter machines were overshadowed by a flying shape that darted like an eagle among sparrows.

the long, tapering hull, and the float attachments, the trim, wicked gun in the bow, proclaimed this giant patrol of the air a fighting sea-plane.

with engines quiet, down dived the great steel-breasted bird; then a swift upturning and she shot level upon the water and rode the waves like a swan.

[156]

a stone could easily have been tossed from the bridge of the submarine upon the upper plane of the aircraft, so near together were they.

the pilot of the sea-plane turned to view the rival factor in modern warfare, half rising as he did so.

mutual recognition flashed across the few separating yards of distance.

“hello, captain!” shouted billy.

“hello yourself, billy barry!” came the answering shout.

“whoopee!” this was josh freeman’s joyful contribution, as he poked a grimy face from the tiny engine room of the big flyer.

“sling us a line,” called the captain.

ned made the cast with a stout bit of hemp, and the aircraft was drawn alongside of the submarine.

“put ’er there, boys,” commanded captain johnson, reaching for billy’s outstretched hand; “and there’s henri, bless you, my lad; give me the grip; sure this is good for sore eyes.”

josh did not stop at handshaking, he encircled both boys in his brawny arms and set their ribs to cracking.

“well, for all that’s out,” exclaimed the captain, spying jimmy, who was just appearing above the hatch, “here’s a whole garden of daisies! tip us your fin, jimmy, and let me tell you that your mother is looking for you.”

[157]

“why, i thought you had gone for a soldier, you dover dandy,” put in josh, as he playfully saluted jimmy.

“here’s another of the flock,” said billy, pushing reddy forward for inspection.

“when i get all of you aboard,” commented the captain, “it will look like i was trying to outdo noah. but come a runnin’ and i’ll pack you all in somewhere, being as there are two lightweights among the four,” referring to jimmy and reddy, “and none of you much heavier than a pound of butter.”

the crew of the submarine came in for some heartfelt expressions of gratitude on the part of the boys, whose lives they had saved, and ned was privately made banker for some tobacco money for the men.

“this is like old times,” contentedly remarked billy, as he heard again the drone of the sea-plane motors.