of preparations for defensive warfare throughout the
civilized world, preparedness that insured so terrible and final a war
that it was literally impossible for a great world conflagration to
again break out. We learned that the present mysterious signs of a
coming war could not possibly have originated in any country on earth,
else they would have been known of long in advance, due to the network
of the Secret Service system. This war, so unexpectedly thrust upon us,
was undoubtedly a war of planets!

"But," objected Hart, "the messages were in English, were they not?"

"They were," continued Secretary Simler, "and that puzzled our experts
in the beginning. But, it may well be that our enemy from out the skies
has had spies among us for many years and could thus have learned our
languages and radio codes. In any event, we are to meet destructive rays
with others equally destructive, and you, Hartley Jones, are the man who
can make our effectiveness certain."

"I?"

"Yes. How long a time will be required in fitting out the _Pioneer_ for
reliable space flying?"

* * * * *

Hart Jones pondered the matter and I could see that he was overjoyed at
the prospect of getting into the thing in earnest. "About one week," he
replied, "providing you can send a force of fifty expert mechanics to my
hangar at once and supply all material as fast as I shall require it."

"Excellent," said the Secretary. "We'll have the men there in a few
hours and will obtain whatever you need, regardless of cost, for
immediate delivery. Incidentally, there will be several scientists as
well, who will supervise the installation of two types of ray generators
and their projecting mechanisms on the _Pioneer_. You will need them
later."

"I don't doubt we shall," said Hart. "And now, with your permission, we
shall leave for the hangar. I'm ready to start work."

"Capital!" Secretary Simler pressed every one of a row of buttons set in
his desk top. We were dismissed.

"Well," said I, when we reached the outside, "he has given you quite a
job, Hart!"

"You said something," he replied. "But, if this threat from the skies
proves as real and as calamitous as I think it will, we all have our
work cut out for us."

"Do you really believe this enemy comes from another planet?" asked
George as we entered the _Pioneer_ for the trip home.

"Where else can they be from?" countered Hart. "But, really it makes no
differe