“Ho, well,” she whispered at last, “there’ll probably be a thaw before we get back or those men will come back and tear it up. But if there isn’t, if they don’t then—well, we’ll see what we’ll see.”
She was still puzzling over these problems when a strange noise, leaping seemingly out of nowhere, smote her ear.
It was such a rumble and roar as she had heard but once before in all her life. That sound had come to her over a telephone wire as she pressed her ear to the receiver during a thunderstorm. But here there was neither wire nor receiver and the very thought of a thunderstorm on such a night was ridiculous.
At first she was inclined to believe it to be the sound of some disturbance on the lake, a sudden rush of wind or a tidal wave.
“But there is little wind and the sea is calm,” she told herself.
She was in the midst of these perplexities when the sound broke into a series of sput-sput-sputs. Her heart stood still for a second, then raced on as her lips framed the word:
“Wireless.”
So ridiculous was the thought that the word died on her lips. There was no wireless outfit on the yacht; could be none on the island, for had they not made the entire round? Had they not found it entirely uninhabited? Whence, then, came this strange clash of man-made lightning? The girl could find no answer to her own unspoken questions.
After a moment’s thought she was inclined to believe that she was hearing the sounds created by some unknown electrical phenomena. Men were constantly discovering new things about electricity. Perhaps, all unknown to them, such isolated points as this automatically served as relay stations to pass along wireless messages.
Not entirely satisfied with this theory, she left the beach and, feeling her way carefully among the small evergreens, came at last to the base of a fir tree which capped the ridge. This tree, apparently of an earlier growth, towered half its height above its fellows.