Jim's arms. The beetle followed
behind him.

"Do any of you know where you are?" asked Jim as he came out.

"I do, sir," said one of the boys. "I live close to here."

"All right, take these youngsters to your house and tell your mother to
telephone their parents to come and get them. If anyone asks you what
happened, tell them to see Jim Carpenter to-morrow. Do you understand?"

"Yes, sir."

"All right, run along then. Now, First Mortgage, let's go hunting."

* * * * *

We wired our captive up so securely that I felt that there was no
possible chance of his escape; then, with Jim at the controls and me at
the guns, we fared forth in search of the invaders. Back and forth over
the city we flew without sighting another spaceship in the air. Jim gave
an exclamation of impatience and swung on a wider circle, which took us
out over the water. I kept the searchlights working. Presently, far
ahead over the water, a dark spot came into view. I called to Jim and we
approached it at top speed.

"Don't shoot until we are within four hundred yards," cautioned Jim.

I held my fire until we were within the specified distance. The newcomer
was another of the Mercurian space-ships; with a feeling of joy I swung
my beam until the cross-hairs of the screen rested full on the invader.

"All ready!" I sung out.

"If you are ready, Gridley, you may fire!" replied Jim. I pressed the
gun button. The crash of the gun was followed by another report from
outside as the radite shell burst against the Mercurian flyer. The
deadly explosive did its work, and the shattered remains of the wreck
fell, to be engulfed in the sea below.

"That's one!" cried Jim. "I'm afraid we won't have time to hunt up the
other right now. This bug told me that the other Mercurians are due here
to-day, and I think we had better form ourselves into a reception
committee and go up to the hole to meet them."

* * * * *

He sent the ship at high speed over the city until we hovered over the
laboratory. We stopped for a moment, and Jim stepped to the radio
telephone.

"Hello, Williams," he said, "how are things going? That's fine. In an
hour, you say? Well, speed it up as much as you can; we may call for it
soon."

He turned both stern motors to full power, and we shot up like a rocket
toward the hole in the protective layer through which the invaders had
entered. In ten minutes we were at the