command them not to act under any
circumstances unless I give the order. Is that clear, Mr. Eitel?"

"Yes, sir!"

I nodded, and turned away, making my way immediately to the navigating
room.

"Mr. Barry," I said quickly and gravely, "I believe that the fate of the
known Universe depends upon us at this moment. We will ascend
vertically, at once--slowly--until we are just outside the envelope,
maintaining only sufficient horizontal motion to keep us directly over
the Control City. Will you give the necessary orders?"

"Immediately, sir!" He pressed the attention button to the operating
room and spoke swiftly into the microphone; before he completed the
order I had left.

* * * * *

We were already ascending when I reached the port forward atomic bomb
station. The man in charge, a Zenian, saluted with automatic precision
and awaited orders.

"You have a bomb in readiness?" I asked, returning the salute.

"Those were my orders, sir."

"Correct. Remove it, please."

I waited impatiently while the crew removed the bomb from the releasing
trap. It was withdrawn at last; a fish-shaped affair, very much like the
ancient airplane bombs save that it was no larger than my two fists,
placed one upon the other, and that it had four silvery wires running
along its sides, from rounded nose to pointed tail, held at a distance
from the body by a series of insulating struts.

"Now," I said, "how quickly can you put another object in the trap,
re-seal the opening, and release the object?"

"While the Commander counts ten with reasonable speed," said the Zenian
with pride. "We won first honors in the Special Patrol Service contests
at the last Examination, the Commander may remember."

"I do remember. That is why I selected you for this duty."

With hands that trembled a little, I think, I drew forth the little vial
of gleaming red metal, while the bombing crew watched me curiously.

"I shall unscrew the cap from this little vial," I explained, "and drop
it immediately into the releasing trap. Re-seal the trap and release
this object as quickly as it is possible to do so. If you can better the
time you made to win the honors at the Examination--in God's name, do
so!"

"Yes, sir!" replied the Zenian. He gave brisk orders to his crew, and
each of the three men sprang alertly into position.

* * * * *

As quickly as I could, I turned off the cap of the littl