On the little reef men watched keenly. Far out at sea, its single funnel tipped with red paint from the crimson sunlight, a little boat tossed and rolled. That boat contained the men who had offered their lives for a chance to kill this Varrhus, who threatened the liberty of the world. Beside the camouflaged hangar two great horns, seeming to be enlarged megaphones, pointed toward the sky. Little wires ran from their points to telephone receivers strapped on the ears of intently listening men. They were microphones to detect the first sound of the musical humming of the black flyer. Teddy and Davis were befurred and goggled, but had pushed up their goggles to take powerful glasses and scan the sky eagerly for a sight of their enemy. Mechanics stood ready at the propellers of the hidden fighting plane, prepared to spin the motors into roaring life the instant the two aviators had settled in their seats. From before the wide doors of the concealed hangar a broad expanse of beach ran smoothly down to the ocean. The little boat tossed and rolled. The men at the microphones listened intently. The others searched the sky. Straight down from a wisp of golden cloud a slim black speck fell toward the earth. At first, so high was it, even those with field glasses could make out only the thin shape of the glistening black body. It fell a thousand, two thousand feet----The whirring disks above the slender body became visible, then the inclosed cabin near the center. The musical humming filled the air. Lower and lower the strange machine dropped. Davis and Teddy were in their seats. "Now!" said Davis sharply, and the propellers whirled. The motors caught, sputtered, and began to run with a steady, droning roar. Davis watched keenly as the black shape slowed in its fall and came to a standstill above the little, tossing boat. Half a dozen men were holding the aëroplane back, and the small shed was full of clouds of choking dust and still more choking fumes from the motor. The black flyer hung motionless, barely three hundred yards above the small boat. There was a long moment of waiting. Then the decks of the boat seemed to fall in. A dozen threatening muzzles were exposed. A dozen flashes of flame shot up from the tiny vessel. Simultaneously Davis cried out, the men released his machine, and it darted forward. He took off from the beach skimmed the waves, and shot out toward the strange combat that was taking place.