pursue them.

Once he shut off the engines and volplaned down a thousand feet or more.
This was done because it was intensely cold up where they were; and the
reasons that had kept them at such a high altitude existed no longer.
Then again Tom wished to listen to discover if there was another
aircraft near them; and this could be done only when his motor was
silent.

"No pursuit, Jack!" he managed to call to his chum before they once more
straightened out, and again allowed the motor to send forth its loud
hum.

Jack had no chance to make any sort of reply. It did not matter, for he,
too, had eagerly listened, and had failed to catch any telltale sound.

Immediately Tom shaped a new course. No longer were they heading toward
the north by east, but directly east. There some forty miles, more or
less, away, lay the city of Metz, the object of their mission.

After moving along in this fashion for a short time Tom drove his
machine more slowly. He was watching for the rising of the old moon
ahead, where the horizon was already lighted with her near approach.

How strange she looked peering above the edge of the world as though
curious to see all that was going on in this troubled hemisphere. Jack
thought he had never witnessed a more peculiar spectacle. But at least
this fragment of a moon would be likely to afford them the necessary
illumination required when they attempted to land in a field that
neither of them had ever seen before, and only knew through information
imparted by means of their chart, and its accompanying notes.

Some other pilot had doubtless been over this same route on previous
occasions; yes, and even landed in that identical field. He had made the
chart; and the accompanying memoranda consisted of his personal
experiences.

Already the moon had dispelled some of the cheerless gloom round about
them. It was still cold up in that upper strata of rarefied air; but
their fur-lined garments kept them from suffering. Besides this, they
were young and vigorous, and their blood was warm, and they were excited
with their mission and able to ignore any physical discomfort that might
come to them.

Jack continued to stare ahead as time passed. He was looking for some
sign of the city towards which they were flying. Tom, on his part, often
took note of his compass, then flashed a glance up at the stars, and
finally sought to discover some landmark far down below that was marked
upon the chart.

He h