tters worse, one of my sparking-plugs was in trouble
again and there was intermittent missfiring in the engine. My heart was
heavy with the fear of failure.

"It was about that time that I had a most extraordinary experience.
Something whizzed past me in a trail of smoke and exploded with a loud,
hissing sound, sending forth a cloud of steam. For the instant I could
not imagine what had happened. Then I remembered that the earth is for
ever being bombarded by meteor stones, and would be hardly inhabitable
were they not in nearly every case turned to vapour in the outer layers
of the atmosphere. Here is a new danger for the high-altitude man, for
two others passed me when I was nearing the forty-thousand-foot mark. I
cannot doubt that at the edge of the earth's envelope the risk would be a
very real one.

"My barograph needle marked forty-one thousand three hundred when I
became aware that I could go no farther. Physically, the strain was not
as yet greater than I could bear, but my machine had reached its limit.
The attenuated air gave no firm support to the wings, and the least tilt
developed into side-slip, while she seemed sluggish on her controls.
Possibly, had the engine been at its best, another thousand feet might
have been within our capacity, but it was still missfiring, and two out
of the ten cylinders appeared to be out of action. If I had not already
reached the zone for which I was searching then I should never see it
upon this journey. But was it not possible that I had attained it?
Soaring in circles like a monstrous hawk upon the forty-thousand-foot
level I let the monoplane guide herself, and with my Mannheim glass I
made a careful observation of my surroundings. The heavens were
perfectly clear; there was no indication of those dangers which I had
imagined.

"I have said that I was soaring in circles. It struck me suddenly that I
would do well to take a wider sweep and open up a new air-tract. If the
hunter entered an earth-jungle he would drive through it if he wished to
find his game. My reasoning had led me to believe that the air-jungle
which I had imagined lay somewhere over Wiltshire. This should be to the
south and west of me. I took my bearings from the sun, for the compass
was hopeless and no trace of earth was to be seen--nothing but the
distant silver cloud-plain. However, I got my direction as best I might
and kept her head straight to the mark. I reckoned that my petrol s