Part 10 (1/2)
”Using the triple mirror to signal to Armand. It is something better than wireless. Wireless requires heavy and complicated apparatus. This is portable, heatless, almost weightless, a source of light depending for its power on another source of light at a great distance.”
I wondered how Armand could ever detect its feeble ray.
”Even in the case of a rolling s.h.i.+p,” Kennedy continued, alternately covering and uncovering the mirror, ”the beam of light which this mirror reflects always goes back, unerring, to its source. It would do so from an aeroplane, so high in the air that it could not be located.
The returning beam is invisible to anyone not immediately in the path of the ray, and the ray always goes to the observer. It is simply a matter of pure mathematics practically applied. The angle of incidence equals the angle of reflection. There is not a variation of a foot in two miles.”
”What message are you sending him?” asked Verplanck.
”To tell Mrs. Hollingsworth to hurry home immediately,” Kennedy replied, still flas.h.i.+ng the letters according to his code.
”Mrs. Hollingsworth?” repeated Verplanck, looking up.
”Yes. This hydroaeroplane yeggman is after something besides jewels to-night. Were those letters that were stolen from you the only ones you had in the safe?”
Verplanck looked up quickly. ”Yes, yes. Of course.”
”You had none from a woman--”
”No,” he almost shouted. Of a sudden it seemed to dawn on him what Kennedy was driving at--the robbery of his own house with no loss except of a packet of letters on business, followed by the attempt on Mrs. Hollingsworth. ”Do you think I'd keep dynamite, even in the safe?”
To hide his confusion he had turned and was bending again over the engine.
”How is it?” asked Kennedy, his signaling over.
”Able to run on four cylinders and one propeller,” replied Verplanck.
”Then let's try her. Watch the engine. I'll take the wheel.”
Limping along, the engine skipping and missing, the once peerless Streamline started back across the bay. Instead of heading toward the club, Kennedy pointed her bow somewhere between that and Verplanck's.
”I wish Armand would get busy,” he remarked, after glancing now and then in the direction of the club. ”What can be the matter?”
”What do you mean?” I asked.
There came the boom as if of a gun far away in the direction in which he was looking, then another.
”Oh, there it is. Good fellow. I suppose he had to deliver my message to Mrs. Hollingsworth himself first.”
From every quarter showed huge b.a.l.l.s of fire, rising from the sea, as it were, with a brilliantly luminous flame.
”What is it?” I asked, somewhat startled.
”A German invention for use at night against torpedo and aeroplane attacks. From that mortar Armand has shot half a dozen bombs of phosphide of calcium which are hurled far into the darkness. They are so constructed that they float after a short plunge and are ignited on contact by the action of the salt water itself.”
It was a beautiful pyrotechnic display, lighting up the sh.o.r.e and hills of the bay as if by an unearthly flare.
”There's that thing now!” exclaimed Kennedy.