Once again he glanced at his watch very anxiously. Then, for the next three-quarters of an hour, while the dusk deepened into darkness, he remained upon his patient vigil.
“At last!” he gasped aloud, as he switched on a little shaded lamp which shone obliquely within the box; then he bent down, and, on a small writing-pad, began to take down rapidly the letters he heard in Morse code—an unintelligible jumble of the alphabet, each nine letters being separated by a space.
Presently there ticked into his ears the three “shorts,” followed by “long-short-long,” which signified “end of work.” Still bending to the tiny light, he took from his pocket a little book. On consulting it, he placed over each code-letter its de-coded equivalent, afterwards reading it to his apparent satisfaction.
Then he rose, standing with his face to the north, and gazing over the wide valley into the night sky. He lit a cigarette, and remained there for a full quarter of an hour. Afterwards he consulted a map from his pocket and then, lighting another cigarette, waited somewhat impatiently. Now and then he could hear the roar of a car or a motor-cycle passing along the high road at the back of him.
About three-quarters of an hour after the reception of the message, Pryor connected up four dry batteries he had in his bag to a lamp with a wide lens, which he placed on its back upon the ground, so that the beams were directed upwards. Then again, after pulling down the wire, he seated himself upon a root of the great tree and waited, listening very attentively.
At last he heard a faint hum in the darkness—a low sound like the distant buzzing of a bee.
It was approaching rapidly—an aeroplane high in the dark sky, for neither moon nor stars showed that night. The machine was approaching from the direction of London, yet, though he strained his eyes, he could not distinguish it in that dark-blue vault above.
On it came rapidly in his direction. Into the electric circuit he had put a little tapping-key and, touching it, he tapped out the Morse letters: “X X D”—his own wireless call number.
Time after time he repeated the call “X X D—X X D!” at the same time straining his eyes into the darkness.
Suddenly, almost exactly above him, he saw, like a tiny star in the sky, a light twinkling. He read the message, and knew that his signal had been seen and read.