"Not as powerful ones as we carry," Darrin answered. "Besides, he has to be at a greater alt.i.tude, when hunting submarines, than it"s handy to drop a bomb from. There is too much margin of chance that the enemy craft will graze by when the bomb is dropped from the air. In our case, if we drop when directly over the Hun, there can hardly be a miss, and it"s the dirigible"s business to tell us when we are directly over the enemy."
In the meantime, on board the destroyer, all was made ready, and Dave followed the same tactics as before. This time, too, there was a normal explosion, though a solid hit was made and the submarine destroyed. Apart from the "blimp"s" report there could be no doubt as to the destruction.
The spread of oil on the surface of the sea told the story.
"If you and we hurry, we may bag another before dark," Dave sent by wireless, as the aircraft started back again.
"We"ll do our best, believe us!" came back the word.
In the late afternoon a slight haze came up, which gradually deepened.
Darrin followed for a few miles, keeping the "blimp" in sight. She was some six miles away when a radio message came from her in code in these words:
"Can you see steamship about four knots north-west of us?"
Dave challenged the lookout on the military mast, but that seaman reported the weather a bit too thick to enable him to make out the steamship. Darrin accordingly wirelessed back this information.
"Looks like a tramp steamer," came the next message, "but she acted suspiciously when she sighted us. Her skipper appears perturbed, which he would hardly be if his business is honest. Weather is thickening so we may lose him in the haze. Better close in."
"Will do so," Dave replied.
Then followed explicit directions as to the course the destroyer must follow.
The next code message from the airship was:
"Skipper of steamship so bothered that he appears to be rigging anti-aircraft gun. Am about to signal him to stop for search."
Despite the haze over the sea the "blimp"s" movements could still be made out from the deck of the destroyer. Mast lookouts and those on bridge and deck followed the "blimp"s" movements with keen interest.
"He maneuvers as if he were closing in on the steamship," declared Ensign Andrews.
"If the steamer"s skipper uses anti-aircraft guns the dirigible"s commander will be justified in dropping bombs," Dave returned. "It"s a stupid piece of business for any lightly armed steamer to attempt to resist a "blimp." But of course the steamer"s skipper does not know that there is a warship so close."
"The rascal"s firing on us," reported the "blimp."
"If you"ll keep back we"ll close in and talk to the stranger," Darrin suggested, by wireless.
"We"re hit," almost instantly came the report from the airship.
"Badly?" Dave asked by radio.
"Investigating. Report soon."
"That ship must be up to something extremely desperate to dare to fire on a British "blimp"!" exclaimed Dave Darrin. "But we"re getting close, and soon ought to know what we have to tackle!"
CHAPTER XVIII
STRIKING A REAL SURPRISE
"ARE we heading straight course?" was Dave"s next question through the air.
"You"re going straight," came the cheering information.
"Found out your hurt?"
"Yes; gas-bag intact, and we"ve withdrawn out of easy range. One motor damaged more than we can repair in air. Can limp home, however."
"Leave the steamship to me," Darrin wirelessed back.
Inside of another minute and a half, Darrin made out the mast-tops of the stranger sticking up from the fringe of haze as the cloudy, reddish curtain shifted.
If Dave had sighted his intended prey, so had the stranger caught sight of the destroyer. The steamship cut a wide circle and turned tail.
"He"s going at nineteen knots, we judge," came the radio report from the "blimp."
"That won"t do him any good!" was the laconic answer that Darrin returned, this time in plain English instead of code.
The lower masts, the stack and then the hull of the stranger became visible as Darrin gained on him.
Bang! A sh.e.l.l struck the water ahead of the stranger, the war-ship"s world-wide signal to halt.
Instead, the stranger appeared to be trying to crowd on more speed.
"Give him one in the stern-post," Darrin ordered.
The sh.e.l.l fell just a few feet short. The third one landed on the after-part of the stranger"s deck-house.
And now there went fluttering up the top of the destroyer"s mast the international code signal:
"Stop or we"ll sink you!"
It took another sh.e.l.l, this one crashing through the stern of the stranger, to convince her skipper that the destroyer was in deadly earnest.
By this time the "Grigsby" was a bare half-mile away, and going fast.
"We"re bringing to bear on you to blow you out of the water," Darrin signalled this time. "Will you stop?"
If he had made any plan to die fighting the fleeing skipper must have lost his nerve at that point, for he suddenly swung his bow around, reduced speed and moved ahead at mere steerage-way.
"Call Ensign Peters to clear away a launch with an armed crew," Darrin directed. "I will accompany him, for I must see what reason that craft had for firing on a British dirigible."
On either bow of the strange steamship was painted the national flag of the same neutral nation to which the "Olga" had appeared to belong. She flew no bunting.
"Stand by to receive boarding party," a signalman on the "Grigsby"s"
bridge wigwagged as the launch started toward the water.