altitude of the guard ships and
Jim asked if anything had been seen. The report was negative; Jim left
them below the layer and sent our flyer up through the hole into space.
We reached the outer surface in another ten minutes and we were none too
soon. Hardly had we debouched from the hole than ahead of us we saw
another Mercurian flyer. It was a lone one, and Jim bent over the
captive and held a hastily made sketch before him. The sketch showed
three Mercurian flyers, one on the ground, one wrecked and the third one
in the air. He touched the drawing of the one in the air and pointed
toward our port hole and looked questioningly at the beetle. The insect
inspected the flyer in space and nodded.

"Good!" cried Jim. "That's the third of the trio who came ahead as
scouts. Get your gun ready, First Mortgage: we're going to pick him
off."

Our ship approached the doomed Mercurian. Again I waited until we were
within four hundred yards; then I pressed the button which hurled it, a
crumpled wreck, onto the outer surface of the heaviside layer.

"Two!" cried Jim as we backed away.

"Here come plenty more," I cried as I swung the searchlight. Jim left
his controls, glanced at the screen and whistled softly. Dropping toward
us from space were hundreds of the Mercurian ships.

"We got here just in time," he said. "Break out your extra ammunition
while I take to the hole. We can't hope to do that bunch alone, so we'll
fight a rearguard action."

* * * * *

Since our bow gun would be the only one in action, I hastily moved the
spare boxes of ammunition nearer to it while Jim maneuvered the Hadley
over the hole. As the Mercurian fleet came nearer he started a slow
retreat toward the earth. The Mercurians overtook us rapidly; Jim locked
his controls at slow speed down and hurried to the bow gun.

"Start shooting as soon as you can," he said. "I'll keep the magazine
filled."

I swung the gun until the cross-hairs of the screen rested full on the
leading ship and pressed the button. My aim was true, and the shattered
fragments of the ship fell toward me. The balance of the fleet slowed
down for an instant; I covered another one and pressed my button. The
ship at which I had aimed was in motion and I missed it, but I had the
satisfaction of seeing another one fall in fragments. Jim was loading
the magazine as fast as I fired. I covered another ship and fired again.
A third one of our enemies f