t was up to Dick and Luke Evans, and they had assumed such a
responsibility as rarely falls to the lot of man in war.

* * * * *

Dick was to lead the flight in a two-seater Barwell plane. This was
one of the latest types, and had been hurriedly adapted to the purpose
for which it was to be used. Dick himself occupied the rear seat, with
its dual controls, and the gun in its armored casing. In front sat old
Luke Evans, in charge of the black gas projector.

His famous camera box, containing a minute quantity of gas in slow
combustion, and projecting the black searchlight, had been built into
the plane. In the rack beside him were a number of the black gas
bombs, each of which, dropped to earth, would release enough gas to
cover a considerable area with darkness. Both Luke and Dick wore
respirators filled with charcoal and sodium thio-sulphate, and beside
Dick a cage containing three guinea-pigs rested.

These little rodents were so sensitive to atmospheric changes that a
quantity of hydrocyanic acid too minute to affect a man would produce
instantaneous death on them.

From its hiding-place off the Virginia coast the American fleet was
steaming hotly southward toward Abaco Island, cruisers, destroyers,
submarines. That Abaco was British territory had simply not been
considered in this crisis of history.

The twelve airships that followed Dick's contained enough bombs to put
the headquarters of the Invisible Empire out of business for good. The
naval guns would complete the same business.

All day Dick and Luke Evans flew southwestward. At first glance,
everything appeared normal. The catastrophe that had fallen upon the
land was visible only in the shape of the lines of tiny figures,
extending for miles, that choked all the roads radiating out of the
principal cities. It was only when they were over the southern portion
of Virginia that the ravages of deadly gas became apparent.

Flying low, Dick could see the fields strewn with the bodies of dead
cattle. Here and there, at the doors of farmhouses, the inmates could
be seen, lying together in gruesome heaps, caught and killed
instantaneously as they attempted flight. Here, too, were figures on
the roads. But they were figures of dead men and women.

* * * * *

They strewed the roads for miles, lying as they had been trapped--men,
women, children, horses, mules, and dogs. The spectacle was an
appal