nce to us now. We have to go after them in earnest. Don't want to
quit, do you, George?"

"Wha-a-at?" shouted George, as he jerked savagely at the main switch of
the _Pioneer_. "You know me better than that, Hart. Did I ever let you
down in anything?"

"No," admitted the smiling Hart, "you never did, bless your heart. But
Jack here is another matter. He has a wife and two kids to look after.
That lets him out automatically."

* * * * *

My heart sank at the words, for I knew that he meant what he said. And,
truth to tell, I saw the justice in his remarks.

"But, Hart," I faltered, "I'd like to be in on this thing."

"I know you would, old man. But I think it's out of the question, for
the present at least. You can help with the reconstruction of the
_Pioneer_, however."

And meekly I accepted his dictum, though with secretly conflicting
emotions. Little did I realize at the time that Hart knew far more than
he pretended and that he had merely attempted to salve his own
conscience in this manner.

I was very anxious to return to my family, and, as I sped homeward in a
taxicab after the _Pioneer_ landed at her own hangar, my mind was filled
with doubts and fears. Secretary Simler had been very brief in his talk,
but his every word carried home the gravity of the situation. What if
these invaders carried the war to the surface? Suppose they seared the
countryside and the cities and suburbs with rays of horrible nature that
would shrivel and blast all that lay in their path? My heart chilled at
the thought and it was a distinct relief when I gazed on my little home
and saw that it was safe--so far. I paid the driver with a much too
large bank note and dashed up my own front steps two at a time.

A few hours later I tore myself away and returned to the hangar, where
the _Pioneer_ now reposed in a scaffolded cradle. The sight which met my
eyes was astonishing in the extreme, for the hangar had been transformed
into a huge workshop with seemingly hundreds of men already at work. It
was a scene of furious activity, and, to my utter amazement, I observed
that the _Pioneer_ was already in an advanced stage of disassembly.

* * * * *

I had no difficulty in locating Hart Jones, for he was striding from
lathe to workbench to boring mill, issuing his orders with the sureness
and decision of a born leader of men. He welcomed me in his most brisk
manner and imm