"Gollyation!" he bawled. "Dem fellers is suah tryin' ter punctuate us!"
Through the blackness of the night a distant voice hailed the pilot of the _s...o...b..rd_.
"Ahoy! ahoy! Who goes there?" was the cry, and it was repeated twice.
CHAPTER V
BETWEEN TWO PERILS
Mark Sampson, having all the mechanism of the flying machine under his immediate control, had it in his power to increase speed and seek to escape the second airship. And Jack wondered why his chum did not immediately send the _s...o...b..rd_ flying at increased speed over the top of Mt. Katahdin and so seek to escape the menace below.
But the young fellow at the controls of the _s...o...b..rd_ had an advantage over his companions that Jack had forgotten. He could hear sounds at a much greater distance than they, and much clearer.
This was because of an invention of Professor Henderson--a small instrument similar to part of the ordinary telephone. The sensitive disk was a form of radio receiver which could be attached to any aviator's helmet, and was being put into general use by pilots. The two boys always adjusted this whenever they were strapped upon the pilot's seat.
Thus, although the report of the gun had sounded but faintly to the other members of the party, to Mark it seemed as though the explosion was within a hundred yards. The voice hailing them likewise seemed to ring in his ears very plainly; and beyond the words somewhat distinguished by his companions the young operator of the _s...o...b..rd_ could make out a further phrase spoken by the person who hailed from the other air-craft.
"Halt in the name of the law!"
Those were the sharp words Mark had caught, and for that reason he hesitated to increase the _s...o...b..rd's_ speed.
In a strap hung near his left hand was a transmitter. Without taking the advice of any of his companions in the flying machine, Mark seized it, put it to his lips, and replied to the hail:
"Ahoy! what do you want?"
Instantly the voice rose from the black abyss below them:
"Heave to! Stop in the name of the law!"
That time the professor and Jack heard the words spoken by their pursuer.
"What do you know about that?" demanded Jack. "'In the name of the law', no less!"
Professor Henderson jumped to the same conclusion that Mark had, and that instantly. "It may be the Secret Service men themselves," he said.
"Ah, Andrew! it is just as well to withhold your fire until we know for sure."
For Andy Sudds had seized his rifle and stood ready to withstand an attack, should such an act become necessary.
Up from the depths came the cry again:
"Hold your ship. I propose to come aboard and search her. In the name of the United States Government!"
Mr. Henderson took the radio telephone out of Mark's hand and replied:
"We wish to know who and what you really are. We will not put ourselves in your power without knowing. We are amply armed."
"Don't you dare to fire upon a United States officer in the discharge of his duty," cried the voice from below, and now the strange airship was much nearer to them. "Who do you claim to be?"
"This is the _s...o...b..rd_, from Easton, Maine, She is manned by her builders, Darrow and Sampson. She carries as pa.s.sengers Washington White, Andrew Sudds and Amos Henderson," declared the professor, in reply. "And she is bound for Alaska."
"Well, well!" exclaimed the voice of their pursuer. "That may all be so. But I have my suspicions. I am Ford, special agent of the Department of Justice. Stand by. Now I am coming aboard."
At a nod from the professor, Mark had already brought the _s...o...b..rd_ to a halt. She lay floating, with all planes extended and without motion of propellers, poised over the summit of Mt. Katahdin.
The descending moon threw its beams over the height and revealed to the vaguely anxious occupants of the _s...o...b..rd_, the other machine darting up from below.
This was a craft of much different aspect from their own. It was a great deal smaller and apparently without half the power possessed by the one built by Jack and Mark.
She shot into the air above their heads at a swift pace, however, and immediately poised over them. In this att.i.tude Ford, as he called himself, had the occupants of the _s...o...b..rd_ completely at his mercy. A bomb dropped upon the huge flying machine would have blown her to pieces. Or, with a gun, he could have picked off one after another of the five people below.
"Stand out of the way, there!" commanded Ford.
Instantly those upon the larger air-craft saw a figure swing down from the framework of the airship above their heads. A light rope ladder unrolled and fell upon the upper deck, or platform of the _s...o...b..rd_, and the man came down this ladder, hand under hand, and in half a minute stood in their midst.
He was a small, gray man--gray suit, gray hair and close-cropped mustache, and gray face, colorless and deeply lined. His age would be hard to judge.
"The _s...o...b..rd_; eh?" he observed, looking sharply from one to the other of the five pa.s.sengers of the huge flying machine. "_You_ are Amos Henderson, sir?" he pursued, nodding to the professor. "I believe I have heard your name before. Professor Henderson, whose scientific discoveries have made us all marvel of late?"
"I am Professor Henderson," said the old gentleman, quietly. "And I can vouch for my companions. These boys, my adopted sons, have built this flying machine, and we are bound for Alaska."
"Indeed! Then I fear I have caused you some slight trouble, not to say delay," said Mr. Ford. "We revenue agents are extremely anxious to overhaul and interview all aviators along the border. You understand?"
"I believe that you have cause to suspect certain flying machines operating between the Canadian towns and Maine settlements," admitted Professor Henderson. "Quite right. And if our suspicions are based on fact, innocent flying men like yourselves may well beware of the fellows we are after. To be frank with you," pursued Mr. Ford, "a band of desperate smugglers are operating by aid of one or more aeroplanes.
And piracy in the air may soon became as frequent--and as grave a peril to innocent aviators--as was ever piracy on the Spanish Main."
"It seems impossible!" said the professor. "Who are these desperate criminals?"
"A man named Bainbridge is at their head. He was originally a diamond dealer and finally was caught smuggling gems into the port of New York.
He had to pay a huge fine and served a term at Atlanta for that crime and since then has sworn to be revenged upon the Government that punished him.
"We learned of late that he was operating on the Mexican border--bringing into the States diamonds that had paid no duty--by aid of a flying machine. But the uprising in Chihuahua and along the border made his work exceedingly dangerous, and he was driven away from that part of the country.
"Now we believe he has joined forces hereabout with ancient enemies of the Federal officers. At least, there is a strange aeroplane reported from both sides of the border, and some fine gems have appeared in the hands of certain suspected dealers in Maine, and as far south as Boston and Providence.
"Bainbridge is known to be a desperate man. Look out for him, Professor.
If you are hailed by another machine, better keep away from it," and the secret service agent laughed. "Had I been in your place I would not have halted on this occasion. You certainly can outsail any airship I have ever seen operated."
Mr. Ford seemed quite satisfied that our friends were law-abiding and he ascended to his waiting craft in a few moments; and the _s...o...b..rd_ started onward again through the starlight.
But the warning of the special agent had impressed the boys as well as the professor. Andy Sudds refused to lie down again, although Jack and Mark continued to operate the flying machine. The old hunter sat with a rifle in his hand for the rest of the night. But the professor went to bed.
An hour after midnight a cloud from the west completely masked the moon and the whole heavens became misty. This cloud brought both wind and rain, and low upon its edge the lightning played fitfully.
"There will be a heavy tempest about dawn," Andy promised the boys.
"I have seen a thunderstorm gather like this before." "But not while you were in a flying machine," chuckled Jack.