It did not soar very high; it skimmed a few hundred feet above the banked darknesses of cumulus that hid the world, ready to plunge at once into their wet obscurities should some hostile flier range into vision.  The tense young steersman divided his attention between the guiding stars above and the level, tumbled surfaces of the vapour strata that hid the world below.  Over great spaces those banks lay as even as a frozen lava-flow and almost as still, and then they were rent by ragged areas of translucency, pierced by clear chasms, so that dim patches of the land below gleamed remotely through abysses.  Once he saw quite distinctly the plan of a big railway station outlined in lamps and signals, and once the flames of a burning rick showing livid through a boiling drift of smoke on the side of some great hill.  But if the world was masked it was alive with sounds.  Up through that vapour floor came the deep roar of trains, the whistles of horns of motor-cars, a sound of rifle fire away to the south, and as he drew near his destination the crowing of cocks....

The sky above the indistinct horizons of this cloud sea was at first starry and then paler with a light that crept from north to east as the dawn came on.  The Milky Way was invisible in the blue, and the lesser stars vanished.  The face of the adventurer at the steering-wheel, darkly visible ever and again by the oval greenish glow of the compass face, had something of that firm beauty which all concentrated purpose gives, and something of the happiness of an idiot child that has at last got hold of the matches.  His companion, a less imaginative type, sat with his legs spread wide over the long, coffin-shaped box which contained in its compartments the three atomic bombs, the new bombs that would continue to explode indefinitely and which no one so far had ever seen in action.  Hitherto Carolinum, their essential substance, had been tested only in almost infinitesimal quantities within steel chambers embedded in lead.  Beyond the thought of great destruction slumbering in the black spheres between his legs, and a keen resolve to follow out very exactly the instructions that had been given him, the man’s mind was a blank.  His aquiline profile against the starlight expressed nothing but a profound gloom.

The sky below grew clearer as the Central European capital was approached.

So far they had been singularly lucky and had been challenged by no aeroplanes at all.  The frontier scouts they must have passed in the night; probably these were mostly under the clouds; the world was wide and they had had luck in not coming close to any soaring sentinel.  Their machine was painted a pale gray, that lay almost invisibly over the cloud levels below.  But now the east was flushing with the near ascent of the sun, Berlin was but a score of miles ahead, and the luck of the Frenchmen held.  By imperceptible degrees the clouds below dissolved....