beyond the power of Potzfeldt.

As Tom had feared, there was no news of his father, but he did not yet
give up all hope.

"If he's a prisoner there's a chance to rescue him," he said.

The time spent in Paris seemed all too short, and it came to an end
sooner than the boys wished. Jack was almost himself again, though he
limped slightly from one of the German bullets in his leg. There was
every hope, however, that this would pass away in time.

Good-byes were said to Bessie and her mother, and once more the two Air
Service boys reported to their aerodrome. There they found not one, but
two, of the big Italian machines, which are capable of long flight,
carrying loads that even the most ponderous bombing plane would be
unable to rise with.

Preparations for the bold dash into the enemy's country went on
steadily and swiftly. Tom and Jack were trained in the management of the
big birds of the air, and though it was essentially different from what
they had been used to in the Nieuports and the Caudrons, they soon
mastered the knack of it, and became among the most expert.

"I believe I made no mistake when I picked them to be part of the
raiding force," said Major de Trouville.

"Indeed you did not," agreed Lieutenant Laigney. "Their work in
discovering the big guns, and their help in silencing them, showed what
sort of boys they are."

And finally the day came when those who were to take part in the raid
across the Rhine were to proceed to a point within the French lines from
which the start was to be made.

Other Italian planes would await them there, and there they would
receive final instructions.

They bade farewell to their comrades in Camp Lincoln, and were given
final hand-shakes, while more than one, struggling to repress his
emotion wished them "_bonne chance_!"

This raid against one of the largest and most important of the German
factory and railroad sections had long been contemplated and details
elaborately worked out for it. The start was to be made from the nearest
point in French-occupied territory, and it was calculated that the big
Italian machines could start early in the evening, cross the Rhine,
reach their objective by midnight, drop the tons of bombs and be back
within the French lines by morning.

Such, at least, was the hope. Whether it would be realized was a matter
of anxious conjecture.

At last all was in readiness. The final examinations of the machines and
their motors had