s of blue bubbles, curving downward again at the end of
their trajectory.

No machines, either French or German, were in sight. Irving had
disappeared some time before we reached the balloon. I had not seen
Drew from the moment when he fired his rockets. He waited until he
made sure that I was following, then started for the west side of the
salient. I did not see him, because of my interest in those clouds of
blue bubbles which were rising with anything but bubble-like
tranquillity. When I was clear of them, I set my course westward and
parallel with the enemy lines to the south.

I had never flown so low, so far in German territory. The temptation
to forget precaution and to make a leisurely survey of the ground
beneath was hard to resist. It was not wholly resisted, in fact.
Anti-aircraft fire was again feeble and badly ranged. The shells burst
far behind and above, for I was much too low to offer an easy target.
This gave me a dangerous sense of safety, and so I tipped up on one
side, then on the other, examining the roads, searching the ruins of
villages, the trenches, the shell-marked ground. I saw no living
thing; brute or human; nothing but endless, inconceivable desolation.

The foolishness of that close scrutiny alone, without the protection
of other _avions_, I realize now much better than I did then. Unless
flying at six thousand metres or above,--when he is comparatively safe
from attack,--a pilot may never relax his vigilance for thirty seconds
together. He must look behind him, below, above, constantly. All
aviators learn this eventually, but in the case of many new pilots the
knowledge comes too late to be of service. I thought this was to be my
experience, when, looking up, I saw five combat machines bearing down
upon me. Had they been enemy planes my chances would have been very
small, for they were close at hand before I saw them. The old French
aviator, worn out by his five hundred hours of flight over the
trenches, said, "Save your nervous energy." I exhausted a three-months
reserve in as many seconds. The suspense, luckily, was hardly longer
than that. It passed when the patrol leader, followed by the others,
pulled up in _ligne de vol_, about one hundred metres above me,
showing their French _cocardes_. It was the group of protection of
Spa. 87. At the time I saw Drew, a quarter of a mile away. As he
turned, the sunlight glinted along his rocket-tubes.

A crowded hour of glorious life it seems