Alden saluted with a blood-stained hand, slipped his gun back into its holster and got up.  He swayed a little, with the swinging slide of the air-liner and with the weakness that nerve-shock of a wound brings.  But coolly enough he slid open the door leading into the main corridor, and passed through, closing the door after him.  Where his hand touched the metal, red stains showed.  Neither man of the pair now left in the pilot-house made any comments.  This was all in the day’s work—­this and whatever else might befall.

Spiraling vastly, up, up climbed the giant plane.  A colder air nipped through the broken window.  Cloud-wisps began to blur the glass; the stars began to burn more whitely in a blacker sky.

The Master touched a button at the left side of the steering-post.  Below his feet, as they rested in their metal stirrups, an aluminum plate silently slid back.  An oblong of dim light blurred up through the heavy plate-glass sheet it had masked.

Glancing down, the Master saw far, far below him a slowly rotating vagueness of waters black and burnished, of faintly twinkling lights.  Lights and water drew backward, as the rotary motion gave way to a southern course.  The Master slowed the helicopters.  A glance at the altimeter showed him 1,965 feet.  The compass in its binnacle gave him direction.

“Pit number one!” he sharply exclaimed into the phone connecting therewith.

“Yes, sir!” came back the observer’s voice.

“Keep a sharp eye out for Niss’rosh!  Remember, two red lights showing there!”

“Yes, sir.  I’ll report as soon as I pick them up.”

The Master, knowing his course thither should be S.E. by S., drew the liner to that exact angle.  Under his skilled touch at the wheel, the compass needle steadied to the dot.  The searchlight lanced its way ahead, into the vague drift of the smoke arising from New York.

“Sight it, yet?” demanded the Master, presently.

“Yes, sir.  Just picked it up.  Hold hard, sir!”

Almost at once, the Master also got a glimpse of two tiny pin-pricks of crimson, high in air above the city-mass.  Swiftly Nissr drew over the building.  Far, very far down in the chasm of emptiness, tiny strings of light—­infinitesimal luminous beads on invisible threads—­marked Broadway, Fifth Avenue, countless other streets.  The two red winks drew almost underneath.

Down plunged the searchlight, picking Niss’rosh out of the gloom.  Through the floor-glass, the Master could descry it clearly.  He slowed, circled, playing with vacuum-lift, helicopters, engines, as if they had been keys of a familiar instrument.  Presently the liner hovered, poised, sank, remained a little over 750 feet above the observatory on the roof-top.

“Cracowicz!” ejaculated the Master, into the phone again, as his deft fingers made another connection.  A foreign voice answered:  “Yes, sir!” alertly.