"Here's Harry!" exclaimed Jack, a moment afterwards, as a wideawake
looking young fellow stopped for a minute near them, being on the way to
his hangar in company with his assistant.

Harry Leroy had become very friendly with the two air service boys,
although they had not known him until long after reaching France. But he
was a genial boy, known to be an unusually clever air pilot and well on
the way to being cited as an American ace, for he had now disabled his
quota of enemy machines.

"They tell me we're going to make a big dent in the Boche lines to-day,
fellows!" he sang out, with one of his genial smiles. "Our commander has
a programme laid out that's said to be pretty ambitious. Some of us are
even hoping it may turn out to be the real start for the Rhine, and that
we'll clean up this old Argonne region pretty soon now."

"Slow but sure is our policy these days, Harry," Tom remarked. "It takes
a heap of time, and makes a hole in our reserves; but the work is done
so thoroughly that it'll stay done. And soon we'll be out of the woods."

"The boys are longing for that day to come," said Harry, about to start
on once more. "They're just sick and tired of this kind of fighting.
Wait till we get Fritz out in the open, and you'll see how well rush him
back like hot cakes! So long, both of you. Here's wishing you the best
of luck and another notch in your stick by nightfall."

Of course Tom had secured another observer in place of the poor fellow
who had been so badly injured on that other flight of his. His arm, too,
had healed.

Shortly afterwards the air service boys received word to start, and
along with four other planes mounted upward like birds on the wing.

So far as appearances went the scene below them did not differ
materially from the preceding day. There was the same vast stretch of
grim forest known as the Argonne, with occasional openings here and
there, "breathing spots," they might be called. These marked sites of
farms, timber or cutting authorized at some past day by the French
government, that controlled the wonderful tract of woods, possibly the
largest in all France. Smoke was already rolling upward in great volumes
while the air pulsated with the fearful crash of every imaginable type
of gun, both large and small. As the day wore on all this was bound to
increase greatly, the impetuous Americans pushing forward and wresting
rod after rod of the forest from the enemy, paying the price witho