ar to shame.

From the information our contact guard had obtained, it appeared that
the Hans had developed a type of "groundship" completely protected by a
disintegrator ray "canopy" that was operated from a short mast, and
spread down around it as a cone.

These ships were merely adaptations of their airships, and were designed
to travel but a few feet above the ground. Their repeller rays were
relatively weak; just strong enough to lift them about ten or twelve
feet from the surface. Hence they would draw but lightly upon the power
broadcast from the city, and great numbers of them could be used. A
special ray at the stern propelled them, and an extra-lift ray in the
bow enabled them to nose up over ground obstacles. Their most formidable
feature was the cone-shaped "canopy" of short-range disintegrator rays
designed to spread down around them from a circular generator at the tip
of a twenty-foot mast amidship. This would annihilate any projectile
shot at it, for they naturally could not reach the ship without passing
through the cone of rays.

It was instantly obvious that the "ground ships" would prove to be the
"tanks" of the Twenty-fifth Century, and with due allowance for the fact
that they were protected with a sheathing of annihilating rays instead
of with steel, that they would have about the same handicaps and
advantages as tanks, except that since they would float lightly on short
repeller rays, they could hardly resort to the destructive crushing
tactics of the tanks of the First World War.

* * * * *

As soon as our first supplies of inertron-sheathed rockets came through,
their invulnerability would be at an end, as indeed would be that of the
Han cities themselves. But these projectiles were not yet out of the
factories.

In the meantime, however, the groundships would be hard to handle. Each
of them we understood would be equipped with a thin long-range "dis"
ray, mounted in a turret at the base of the mast.

We had no information as to the probable tactics of the Hans in the use
of these ships. One sure method of destroying them would be to bury
mines in their path, too deep for the penetration of their protecting
canopy, which would not, our engineers estimated, cut deeper than about
three feet a second. But we couldn't ring Nu-Yok with a continuous mine
on a radius of from five to fifteen or twenty miles. Nor could we be
certain beforehand of the direction of th