Astounding Stories of Super-Science July 1931: VOL. VII, No. 1 - The Doom from Planet 4

"SO S. S O S. S O S." Three short, three long, three short, the flashes winked from the dark headland. Dan McNally, master and owner of the small and ancient trading schooner, Virginia, caught the feeble flickering light from the island as he strode across the fore-deck. He stopped, stared at the looming black line of land beneath the tropical stars. Again light flashed from a point of rock far above the dim white line of phosphorescent surf, spelling out the signal of distress.