If the gas and the gravity neutralizer worked as Professor Henderson hoped they would, as soon as the ship was completed, all that would be necessary to start on the voyage would be to fill the aluminum bag and set the air compressor in motion.
The gas was made from common air, chemically treated and with a secret material added which by means of a complicated machine in a measure did away with the downward pull of the earth. Thus all that was necessary to carry on a long voyage was a quant.i.ty of gasolene to operate the engine which worked the electric machines, and some of this secret compound.
The professor and his helpers had been working to good advantage. At last all was in readiness for the gas test.
It was proposed to try it on an experimental scale. Some of the fluid was to be generated and forced into an aluminum cylinder under the same pressure it would be used in the air ship. To this cylinder were attached weights in proportion to the weight of the Flying Mermaid with its load of human freight, engines and equipment.
"This cylinder is just one one-hundredth the size of the cylinder of the ship," said the professor. "I am going to fasten to it a hundred pound weight. If it lifts that our latest contrivance will be a success."
"You mean if the little cylinder pulls a hundred pounds up the big ship will take us and the machinery up?" asked Mark.
"Certainly," answered the professor. "If this cylinder lifts a hundred pounds, one a hundred times as big (as that of the Mermaid is), will lift a hundred times as much, or ten thousand pounds. That is five tons, or more than a ton over what I figure to be the weight of our ship and contents. The latest war balloon can lift one ton with ease, and if my machine can not do five times as well I shall be disappointed."
The last adjustments were made, pipes were run from the gas generator to the cylinder, and the hundred pound weight was attached.
"Everybody look out now," said Mr. Henderson. "I am going to start the machine and let the gas enter the cylinder. It is a very powerful gas and may break the cylinder. If it does you must all duck."
The scientist gave a last look at everything. The boys got behind some boards whence they could see without being in danger. Washington, who had little fear so long as there was no danger of going under ground, took his place at the dynamo. Andy Sudds, with Bill and Tom, stationed themselves in safe places.
"All ready!" called the professor.
He pulled a lever toward him, turned a wheel and signalled to Washington to start the dynamo. There was a sound of buzzing machinery, which was followed by a hiss as the gas began to enter the cylinder under pressure. Would it stand the strain? That question was uppermost in every one"s mind save the professor"s. He only cared to see the cylinder leave the ground, carrying the weight with it. That would prove his long labors were crowned with success.
Faster and faster whirred the dynamo. The gas was being generated from the air. The secret chemical made a hissing which could be heard for some distance. The gage registered a heavy pressure. Anxiously the professor watched the cylinder.
"There!" he exclaimed at length. "It has all the gas it can hold. Now to see if it works!"
He disconnected the pipe leading from the generator. This left the cylinder free. It seemed to tremble slightly. There appeared to be a movement to the hundred pound weight which rested on the ground. It was as if it was tugging to get loose.
"There it goes! There it goes!" cried Mark, joyfully.
"Hurrah!" shouted Jack. "There she rises!"
"It suttinly am projectin" itself skyward!" yelled Washington, coming from the dynamo.
Sure enough the cylinder was slowly rising in the air, bearing the weight with it. It had lifted it clear from the ground and was approaching the roof of the big shed.
"It will work! It will work!" exclaimed the professor, strangely excited.
The next instant the cylinder, carrying the weight, sailed right out of an open skylight, and began drifting outside the shop, and across the fields.
"Quick! We must get it back!" cried Mr. Henderson. "If it gets away my secret may be discovered and I will lose all! We must secure it!"
But the cylinder was now two hundred feet in the air and being blown to the east, the weight dangling below it, making it look like a miniature airship.
"We can never catch that!" cried Mark.
CHAPTER III
WASHINGTON DECIDES
"WE must catch that cylinder!" the professor exclaimed. "Some one may find it when it comes down and a.n.a.lyze the gas. Then he would discover how to make it. The cylinder must come down!"
"Don"t see how we can proximate ourselves inter th" vicinity of it lessen we delegate th" imperial functions of orinthological specimens t" some member of this here party," observed Washington.
"If you mean we can"t catch that there contraption unless we turn into birds I"ll show you that you"re mistaken!" cried Andy Sudds. "I guess I have a trick or two up my sleeve," and the old hunter quickly threw open the breech of his gun and inserted a couple of cartridges.
He raised the piece to his shoulder and took quick aim. There was a sliver of flame, a puff of smoke and a sharp report. The professor and the boys who were watching the cylinder saw it vibrate up in the air.
Then there came a whistling sound. An instant later the metal body began to descend, and it and the weight fell to the earth.
"I"m sorry I had to put a bullet through it, Professor," said old Andy with a queer smile, "but it was the only way I saw of bringing it down. Hope it isn"t damaged much."
"It doesn"t matter if it is," the scientist answered. "I can make more cylinders, but I don"t want that secret of the gas to become known.
Your bullet served a good turn, Andy, for it let the compressed vapor out just in time."
"Then we may consider the experiment a success," said Mark, as Washington went to where the cylinder had fallen, to detach it from the weight and bring both to the shed.
"It seems so," Mr. Henderson answered. "True, it was only an experiment. We have yet to test the ship itself."
"When can we do that?" asked Jack.
"I hope by Monday," the scientist answered.
"Will you try it in the water or air first?" asked Mark.
"I"m almost certain it will float in the water," the aged inventor said. "It does not require much work to make a ship which will do that. But the air proposition is another matter. However, since the cylinder rose, I am pretty sure the Flying Mermaid will.
"But we have done enough work to-day. Let"s rest and have something to eat. Then, with Sunday to sit around and talk matters over, we will be ready for Monday"s test."
Some of the game Andy had killed was soon on the table, for Washington, in addition to his other accomplishments, was an expert cook. During the evening the boys and their friends sat in the living room of the big shed and talked over the events of the day.
Sunday was spent in discussing what adventures might lie before them should they be able to descend into the big hole. Washington did not say, much, but it was easy to see he had no notion of going. He even began to pack his few belongings in readiness to leave the service of Mr. Henderson, for whom he had worked a good many years.
No one remained long abed Monday morning. Even Washington was up early in spite of the interest he had lost in the professor"s voyage.
"I jest wants t" see yo" start fer that place where they buries live folks," he said.
In order to properly test the Flying Mermaid it was necessary to move the craft from the shed from which place it had never been taken since it"s construction was started. It had been built on big rollers in antic.i.p.ation of this need, so that all which was now necessary was to open the doors at the end, and roll the craft out.
This was accomplished with no small amount of labor, and it was nearly noon before the big ship was moved into the open. It was shoved along to a little clearing in front of the shed, where no trees would interfere with its possible upward movement.
Everyone was bustling about. The professor was busiest of all. He went from one machine to another; from this apparatus to that, testing here, turning wheels there, adjusting valves and seeing that all was in readiness for the generating of the powerful gas.
As the airship was half round on the bottom and as it rested in a sort of semi-circular cradle; it brought the entrance some distance above the ground. To make it easier to get in and out while preparations for the trial were going on, Bill and Tom had made an improvised pair of steps, which were tied to the side of the ship with ropes.