Indeed, the odd-shaped hull, with its naked frame and two gaunt aerial propellers, did look strangely incomplete. But the boys knew that the wings were all ready for instant attachment. In fact, it was one of the features of the _Sea Eagle_ that the craft was capable of being taken to pieces and put together again with very little loss of time or labor.
As the hydroplane portion of the _Sea Eagle_ floated clear of the weighted frame in which it had made its journey to the beach, Frank looked inquiringly at the inventor. His hand was on the self-starting device which put the powerful motor in operation. Dr. Perkins was actually pale, and Frank could see that his strong hand shook perceptibly as he nodded his head.
But he mastered his nervousness quickly, and, grasping the steering-wheel in a firm grip, he spoke:
"You can start up now," he said.
Frank turned the starting handle, admitting a charge of gas to the cylinders. Then he pressed a b.u.t.ton and instantly the motor responded with a roar and a series of explosions, like those of a battery of gatling guns going into action. Having started it he admitted gasolene, and adjusted the carburetor till the cylinders were all working steadily.
Close to Dr. Perkins" hand was a lever. This, when moved, "threw in" the clutch connecting the motor with the driving mechanism. Directly Frank had finished tuning up the motor Dr. Perkins" hand reached for the lever. He jerked it nervously back. There was a whirr and a buzz, as the chains whirled the twin propellers round, and at the same instant the _Sea Eagle_ darted forward like an arrow from a bow.
Faster and faster she went, getting up speed with seemingly marvelous rapidity. But instead of driving deeper into the water, under the pressure of the aerial propellers which rushed her forward through the atmosphere, the faster the _Sea Eagle_ was driven the more lightly did the craft skim the surface of the water, till at top speed-2,000 revolutions a minute-her bottom barely touched the water. This was owing to the peculiar construction of the hull, which was designed so as to "plane" the water in exactly the manner it did.
Cheer after cheer broke from the lads on sh.o.r.e as they saw the swift craft dart off, slicing the tops of the small waves like a cream skimmer. Dr. Perkins circ.u.mnavigated the island three times before he gave the signal to Frank to slow down. Then, releasing the clutch, the inventor allowed the _Sea Eagle_ to come to rest, with its bow almost touching the beach.
"Now we will have a weight test," he announced; "come on, boys."
The lads ash.o.r.e surely needed no second invitation. Without bothering to remove shoes or stockings they waded into the water and out to the _Sea Eagle"s_ side. In less time than it takes to tell it they were swarming over the side of the c.o.c.kpit and struggling for positions near the engine. But Dr. Perkins made them arrange themselves so that their weight would be evenly distributed. Ben Stubbs and Harry sat in the extreme stern, while Pudge and Billy occupied opposite seats amidships.
This done, off darted the _Sea Eagle_ once more, and speedily set at rest all doubts as to her capability to "plane," or skim the water, under an added load.
"It"s like riding on a floating island over a sea of raspberry ice cream soda," declared Billy, when he was asked later to describe his sensations.
But a severer test awaited the _Sea Eagle_, namely, the trying out of her capacity actually to rise into the air. The craft was run partially ash.o.r.e, and the great wings bolted in place and the stay wires adjusted.
The stay wires were tightened by turn buckles till they were taut as fiddle strings, a.s.suring stability of the wings. But in addition the wings were, of course, partially supported on the light but strong skeleton framework before noticed.
Much to the disappointment of the others, only Frank and Harry Chester and Dr. Perkins were to partic.i.p.ate in the flying trials. But they took it all in good part, being promised rides later if the tests were successful. As before, the _Sea Eagle_, after she had been backed off and the propellers started, skimmed along the top of the water like a flying fish. But all at once the watchers on sh.o.r.e saw her rise bodily from the water and soar upward into the air. Higher and higher went the craft, gliding like a gull through the ether. It was an inspiring sight, and a perfect tornado of yells broke from Ben Stubbs, Billy and Pudge.
But those on board the _Sea Eagle_ could not hear the sounds of enthusiasm above the roaring of the motor.
Under Dr. Perkins" skillful guidance the _Sea Eagle_ climbed the aerial staircase till a height shown by the barograph to be almost 4,000 feet had been attained.
"Now to test the buoyancy apparatus," cried the doctor suddenly. "Shut off power, Frank."
Frank, who knew what was coming, obeyed the order and turned a valve admitting the pure hydrogen gas from one of the cylinders into the buoyancy devices. Instantly the upper wings swelled, till they resembled puffed-out mattresses more than anything else, and the "volplaning"
downward movement was perceptibly checked. But, setting the descending device, Dr. Perkins headed the _Sea Eagle_ for the water, and, skillfully manipulating the craft, landed it as lightly as a drifting feather on the water by the hull of the _Betsy Jane_.
Now came a further trial of the capabilities of the wonderful new craft which, so far, had proven such a success. Dr. Perkins set the planes in a rising position and allowed the _Sea Eagle_ to hover above the _Betsy Jane_, like the bird for which the aerial craft had been named. Then suddenly he began a rapid descent, landing finally on the very summit of the inclined runway before mentioned. The sides of the _Sea Eagle_ were equipped with large metal hooks, which were hastily thrown out by the boys and attached to four "eyes" arranged to receive them.
When this had been done the suction pump was set to work, and the inflated wings emptied of the gas, which was forced back into its receiver, and the valve closed. It was calculated that less than two per cent of the gas was lost during the process. The _Sea Eagle_ was now once more a simple hydroplane, without any buoyancy device.
At a word from Dr. Perkins the hooks which had held the machine in place were disengaged, and instantly the craft began to glide down the runway.
Half way down the engine was started, and when the graceful craft reached the abrupt end of the incline, the _Sea Eagle_ went soaring off into s.p.a.ce like a huge white-winged bird. This test was regarded by Dr.
Perkins as the most important, for it proved the entire practicability of launching the _Sea Eagle_ from a ship far out on the ocean.
After circling in the air a few times the tests were concluded by a rapid drop toward the earth right above the summit of the island. Just as it seemed as if the new craft must end her career by being dashed to bits against the construction shed, a skillful twist of the steering device sent her soaring upward once more. Two more swinging aerial loops were described, and then, with hardly a jar or vibration, the _Sea Eagle_ was brought to rest by her inventor, almost in front of the shed where she had been a.s.sembled.
As the thrilling and wonderful trip was concluded, the boys came pressing about Dr. Perkins, showering congratulations and good wishes.
"Why, one could fly across the ocean in such a craft," declared Frank enthusiastically.
The others laughed, but, to their astonishment, Dr. Perkins looked perfectly serious.
"I have a long trip in view," he said, "a flight that will test every wire and bolt in the _Sea_ _Eagle"s_ construction. I did not announce this before for I wished first to see if everything worked satisfactorily."
"No doubt about that," said Billy Barnes with enthusiasm. He had been dodging about the great flying machine, taking photos from every possible angle.
"No," admitted Dr. Perkins; "I must say that so far the _Sea Eagle_ is all that I could desire. But the final test will put that beyond the shadow of a doubt. Do you boys wish to undertake a long trip?"
"Cookies and cuc.u.mbers! Do we!" roared Pudge, as the others pressed eagerly about to hear the unveiling of the doctor"s plan.
CHAPTER X.-"C. Q. D.!"
But they were compelled to curb their impatience till that evening after supper, for the doctor set every one busily to work "stabling" the _Sea Eagle_ and attending to the engines after the hard test they had undergone. Every part was carefully gone over, and it was found that despite the strain of the novel craft"s first try-out, nothing save a few minor adjustments were required.
"Now, dad," said Pudge, after the dishes had been washed and Ben had his pipe going, and the others were perched on the edge of the lower bunks, like so many birds on a rail, "now, then, dad, we are ready to hear your plans for that cruise."
Dr. Perkins smiled.
"I"m afraid, my boy," he said, "that you are in for a disappointment.
While I thoroughly believe the _Sea Eagle_ is capable of conveying our whole party through almost anything, I am unwilling to place too great a burden on her at her first long-distance trial."
Pudge"s face lengthened.
"Oceans and octopuses!" he groaned, "I s"pose I"m to be left behind, as usual."
"I"m afraid it will be necessary," was the reply; "you see, there will only be room under my present plan for experienced navigators. But not to keep you in suspense any longer, my present plan is to cruise down the coast to Florida, round that peninsula, and then fly up to New Orleans, and then possibly I might test out the _Sea Eagle_ still further on a flight up the Mississippi."
"Wow! And we"re to miss all that?"
"Not _all_ of it, Pudge," smiled the doctor. "I was planning to send you and Billy on ahead to meet us at New Orleans and make arrangements for our arrival there."
"Cookies and catamounts! That"s not so bad. I"ve always longed to see New Orleans. But, then, would you take us with you up the Mississippi?"
"If we go-yes."
"Look a-here," struck in Ben"s ba.s.s voice at this point, "I don"t want to b.u.t.t in, or nothing like that, doctor; but this here is a cruise that just suits me. Would you have any objection if I went along with ther boys ter New Orleans?"
"Why, I hadn"t thought of it," confessed Dr. Perkins.
"You see, I"ve got some partic"lar business down that way," said Ben, with a portentous wink at Harry; "ain"t I, Harry?"
The boy addressed instantly guessed that Ben referred to the supposed treasure trove lying at the bottom of the Black Bayou. Now, in the rush of events following Harry"s return from his strange cruise on the _Betsy Jane_, he had quite forgotten about Raoul Duval"s map. But now it flashed back on him, and the recollection caused him to flush with excitement.
Dr. Perkins looked puzzled, while a glance of intelligence shot between the grizzled old adventurer and the boy.