Ned presented himself at High Towers betimes the next morning. He found Jack Chadwick and Tom Jesson awaiting him at the workshop. Mr. Chadwick was in New York attending to some business connected with his interests. Mr. Jesson was in Boston delivering a series of biological lectures, so that the boys had the place to themselves.

The eagerness of Ned to know the verdict of the two Boy Inventors must have shown itself very plainly on his face, for almost as soon as he had been introduced to Tom Jesson, Jack hastened to relieve the lad’s anxiety.

“I suppose you want to know if it’s good news or bad?” asked Jack.

“I’ve hardly slept all night thinking of it.”

“Then I have something to tell you that you will be glad to hear. We will help you manufacture the craft your uncle designed and——”

Ned’s glad outburst of thanks checked him for a moment, but Jack went on to explain that he and his cousin would take only one-quarter interest in the craft, leaving the remainder free and clear to Ned. The cost of manufacturing would be borne by the Boy Inventors and the patents, when the machine was completed, would rest in Ned’s name.

“Is that satisfactory?” asked Jack when he had finished.

“Satisfactory!” burst out Ned. “It’s generous—too generous!”

“Not at all. So far as money is concerned, when you know more about us, you will know that Tom and I have plenty, most of it realized from our inventions.”

“I know but——”

“Hold on a minute. Here we are, just dying for a chance to get to work on something really new and neither of us with brains enough to think up anything. You come along with just what we are looking for and we feel more like thanking you than considering we are doing anything wonderful.”

“Besides,” added Tom, “even one-quarter interest in the electric hydroaeroplane ought to yield a handsome profit.”

“If, and it’s a big ‘If,’” said Ned with a laugh, “we can get it to work. If not——”

“We wouldn’t tackle it if we didn’t think it was practicable,” said Jack decisively. “So that ends that. Now come along, Ned, and be initiated into the mysteries of the firm, for you know, you are now a working partner.”

“Say, fellows!” burst out Ned enthusiastically. “I don’t know how to thank you——”

“That’s all right. You help us out on building the machine and that will be thanks enough. When we’ve got it working, we’ll shine in your reflected glory and that will be satisfaction enough for us.”

The next hour was one of unmixed delight for Ned, interested, nay wrapped up in mechanics as he was. He had never seen a workshop fitted up on such a scale as that of Jack Chadwick and Tom Jesson,—a private workshop, that is. Lathes and all sorts of machinery of the latest pattern were driven by a powerful gasolene engine. Facilities were at hand for making the parts of many of the boys’ devices. Three skilled machinists were also employed, and summoning them about him, Jack Chadwick briefly outlined to the interested men the big task they were about to undertake.

He was in the midst of his explanations, when Sam Hinkley strolled in. Jack looked at him sharply. One of his eyes was swollen and slightly discolored. He glared at Ned savagely and the look was not lost on Jack Chadwick.

As soon as he had an opportunity, Sam drew Jack aside and demanded, in an indignant and aggrieved voice, to know if Ned Nevins was to work in the shop.

“Yes, and on a partnership basis, too,” said Jack enthusiastically. “He has been the means of introducing us to a wonderful invention. We are going to start in on the work of its construction right away.”

Sam did not appear interested in this information except that a jealous look crept into his eyes.

“I think you ought to know that he’s nothing but a rowdy,” he said. “I’ll bet any invention he’s been telling you about is a fake.”

“The plans look good to us,” responded Jack, “and we are going to risk it. What have you got against the boy, anyhow?”

“He’s a rowdy,” repeated Sam. “He blacked my eye last night.”

Jack, who had a pretty good insight into Sam’s character, could not repress a smile.

“I thought you were invincible, Sam.”

“He didn’t fight fair. He forced me into a row,” grumbled Sam. “I could have licked him all right if——”

“What had you been doing, Sam?”

“Nothing. He took my chair away and when I wanted it back he said I’d have to fight for it and——”

“And you did,” commented Jack with a dry smile. “Well, Sam, my advice is to forget it. If you think you’ve been injured I’m sorry, but Ned Nevins appears to me to be an inoffensive sort of a lad, quiet and unassuming.”

“Oh, he just puts on that to fool you,” muttered Sam.

At this juncture, Jack was called away by one of the machinists and Sam, with a very bad grace, turned to some unfinished work at his lathe. He was still engaged at this when Ned happened to pass by.

“I got your note last night, Hinkley,” he said. “Why didn’t you give it to me in person instead of slipping it under the door?”

Sam made a sound resembling “G-r-r-r-r-r” and went on with what he was doing.

“As I suppose you know,” resumed Ned, “we shall see a good deal of each other in the future. Why can’t we be friends?”

Sam’s face contorted with rage as he dropped the tool he had been using and faced round on Ned.

“Because I hate you, that’s why. You’re nothing but an interloper and a faker and Jack Chadwick will find it out before very long.”

“I’m sorry you think that, Sam.”

“Why?” asked Sam, surprised at the other’s calm, even tone. His outburst appeared to have no effect whatever upon the lad he had desired to impress with his enmity.

“Because I am afraid you are going to be disappointed,” and with these words Ned passed on.

The next few weeks were busy ones about the workshop of the Boy Inventors, but gradually, almost imperceptibly, the electric hydroaeroplane began to take shape. The enthusiasm of the boys infected the workmen and even Sam Hinkley appeared to work with more than usual fervor.

Briefly described, the hydroaeroplane portion of the craft consisted of two twin boats, each about forty feet in length and constructed of a special aluminum alloy jointed together by strong vanadium connections. Between the pair of boats, which will be more fully described later, the storage tanks, which were the novel feature of the Jeptha Nevins craft, were placed.

In the center of each of the boats was a small raised cabin, the cabins being connected by a hollow passageway. At either end of the craft the wings, of biplane pattern, were attached. The wing spread was ninety-five feet which, with the craft’s electric engines of enormous power, gave the giant air-craft a lifting capacity of two thousand pounds.

Above the storage batteries, and between the twin “boats,” were the motors, each coupled to two sets of propellers placed fore and aft on either end of the craft and outside of the wings. A light, but strong, framework supported the outer bearings of the propellers and served to give them sufficient projection to insure balance. The forward set of propellers were so “pitched” as to pull the craft through the air, while the after ones furnished a driving impulse.

One of the most important features of the invention was the device by which electricity was made while she was in flight or skimming over the water. This was a generator of considerable power geared to the shafts of the propellers. As the craft drove along, the storage batteries were constantly recharged by this device. For the initial, or starting “charge” the batteries were furnished with “juice” by a small compressed air-driven generator which could also be used in case of accident to the automatically driven device. Thus the necessity of gasolene was done away with and the Nevins craft was equipped, so far as power was concerned, to cross the Atlantic Ocean. But, of course, no such project entered into the minds of her young constructors.

The planes themselves were covered with sheets of aluminum attached to frames of radiolite, a metal as light as aluminum and of great tensile strength. Landing wheels, supported by powerful shock absorbers, provided for alighting, and special balancing devices, attached to the bow and to the stern of the novel craft, minimized the danger of coming to earth with too great a shock to the weighty fabric.

On the top of each cabin was a powerful search-light, and each was fitted out with two bunks and other conveniences as in the stateroom of an ocean liner. The pilot house was mounted above the covered passage, or tube, already referred to, which connected the two parts of the craft. It contained a wheel not unlike that of an ocean liner and levers to control the balancing wings and the pitch of the planes.

As for the engine-controls, the motor being electrically driven, the machinery to control it was wonderfully simple. An apparatus not unlike a switchboard, as may be seen in any powerhouse, was mounted within convenient reach of the helmsman. The light controls also were affixed to this board. Mastery of the huge craft was within instant power of the driver. A signaling system to each cabin, in case of emergency, was another feature added to the general completeness of the equipment.

Such is a brief description of the Nevins electric hydroaeroplane, a craft in which the Boy Inventors were destined to meet as strange adventures as had ever fallen to their lot.