escended. He and George
watched through one of the floor ports and I followed suit. We were
falling, unhampered by air resistance, and our bodies were practically
weightless with reference to the _Pioneer_. It was a strange sensation:
there was the feeling of exhilaration one experiences when inhaling the
first whiff of nitrous oxide in the dentist's chair--a feeling of
absolute detachment and care-free confidence in the ultimate result of
our precipitous descent.

I found considerable amusement in pushing myself from side to side of
the cabin with a mere touch of a finger. There was no up nor down, and
sometimes it seemed to me that we were drifting sideways, sometimes that
we fell upward rather than downward. Hart and George were unconcerned.
Evidently they were quite accustomed to the sensations. They bent their
every energy toward discovering what had caused the disaster to the
SF-22 and its convoy.

For several hours we cruised about on the strangest search ever made in
the air. Alternately shooting skyward to unconscionable altitudes and
dropping to levels five and six to replenish our fuel supply, we covered
the greater portion of the United States before the night was over. But
the powerful searchlight of the _Pioneer_ failed to disclose anything
that might be remotely connected with the disappearance of the SF-22.

For me it was a never-to-be-forgotten experience. Lightning dashes from
coast to coast which required but a few minutes of time--circling many
miles above New York or Washington or Savannah in broad daylight with
the sun low on the up-curved horizon; then shooting westward into the
darkness and skirting the Pacific coast less than fifteen minutes later,
but with four hours' actual time difference. Space and time were almost
one.

* * * * *

Hart had not provided the _Pioneer_ with a radio or television
transmitter, but there was an excellent receiver, and, through its
agency we learned that the world was in a veritable uproar over the
latest visitation of the mysterious terror of the sixth air level. All
commercial traffic in levels four, five and six was ordered
discontinued, and the government air control stations were flashing long
messages in code, the import of which could but be guessed. Vision
flashes showed immense gatherings at the large airports and in the
public squares of the great cities, where the general populace become
more and more excited and ter