ting growl of the distant barrage kept the nerves of the city's
inhabitants on edge, there was an explosion near the top of a pinnacle
not far from the Imperial Tower. It occurred at the 732nd level, and
caused the structure above it to lean and sag, though it did not fall.

Repair men who shot up the shafts a few minutes later to bring new
broadcast lamps to replace those which had been shattered, reported what
seemed to be a sphere of metal, about three feet in diameter, with a
four-inch lens in it, floating slowly down the shaft, as though it were
some living creature making a careful examination, pausing now and then
as its lens swung about like a great single eye. The moment this "eye"
turned upon them, they said, the ball "rushed" down on them, crushing
several to death in its vicious gyrations, and jamming the mechanism of
the elevator, though failing to crash through it. Then, said the wounded
survivors, it floated back up the shaft, watchfully "eyeing" them, and
slipped off to the side at the wrecked level.

The next night several of these "air balls" were seen, following
explosions in various towers and sections of the city roof and walls. In
each case repair gangs were "rushed" by them, and suffered many
casualties. On the third night a few of the air balls were destroyed by
the repair men and guards, who now were equipped with disintegrator
pistols.

This, however, was pretty costly business, for in each case the ray
bored into the corridor and shaft walls beyond its target, wrecking much
machinery, injuring the structural members of that section, penetrating
apartments and taking a number of lives. Moreover, the "air balls,"
being destroyed, could not be subjected to scientific inspection.

After this the explosions ceased. But for many days the sudden
appearances of those "air balls" in the corridors and shafts of the city
caused the greatest confusion, and many times they were the cause of
death and panic.

At times they released poison gases, and not infrequently themselves
burst, instead of withdrawing, in a veritable explosion of disease
germs, requiring absolute quarantine by the Han medical department.

There was an utter heartlessness about the defense of the Han
authorities, who considered nothing but the good of the community as a
whole; for when they established these quarantines, they did not
hesitate to seal up thousands of the city's inhabitants behind hermetic
barriers enclosing entire