n, "Are you there? You
remember that big bad man, the one who used heaps of power on 1200?
Well, he's gone north--very far north. You'd want to follow him, Curlie,
if you knew what I know. The radiophone is going to do great things for
the north, Curlie. But men like him will spoil it all. Remember this,
Curlie: If you do go, be careful. Careful. He's a bad man and the stakes
are big!" The whisper ceased. The silence that followed it was ghostly.

"And that," Curlie whispered softly, "came all the way from my dear old
home town. She thought I was still in the secret tower room. Fine chance
of my following that fellow up north. But when I get back I'll
investigate. There may be something big there, just as she says there
is. Yes, I'll look into it when I get back--if I do get back."

He shivered as he caught the howl of the wind in the rigging. Then,
tuning his instrument back to 600, he listened once more for some
message from the seaplane, the _Stormy Petrel_.

CHAPTER XV

S. O. S.

The spot of light which raced across the waters of the sea where no land
was to be seen, where the black surface of the swiftly changing waters
shone always beneath the occupants of the seaplane, took on an ever
widening circle. There appeared to be no end to Alfred Brightwood's
belief that somewhere in the midst of all this waste of waters there was
an island.

Vincent Ardmore had long since given up hope of becoming rich by this
mad adventure. His only hope, the one that gave strength to his arms
benumbed by long clinging to the flashlight and new sight to his eyes,
weary with watching, was that they might discover some bit of land, a
coral island, perhaps, where they might find refuge from the sea until a
craft, called to their aid, might rescue them.

The thought of returning to the mainland he had all but abandoned. The
gas in the tank was too low for that; at least he was quite certain it
must be.

There was a chance, of course, that if they alighted upon the water and
sent out an S. O. S., the international call for aid, they would be
answered by some near-by ship. But this seemed only a remote
possibility. He dared not hope it would happen. They were far from any
regular course of trans-Atlantic vessels and too far from shore to be
picked up by a coast vessel or a fishing smack. The very fact that this
island, marked so plainly on the ancient map, had been in this
particular spot, so remote from the main sea-roads,