f
big guns.

But for many a day the story of the wasps at headquarters was told up
and down the firing line.

It was about a week after this, when preparations for the big attack
had almost reached completion, that the three chums, having an hour or
so to spare, thought to call on Professor Snodgrass. They went to the
little house in the French village where he had been staying, and
inquired for him.

"He has disappeared, Messieurs," answered the old woman who looked
after the place.

"Disappeared!" echoed the boys blankly.

"Yes, Messieurs. He went out yesterday morning without his hat to
chase after a butterfly he saw in the garden, and he did not come
back. He has disappeared. I am sorry, for he was a nice man, though a
trifle queer at times."

"Well, what do you know about that?" gasped Jerry, while his chums
looked at him in wondering amazement.

CHAPTER XXVII

ST. MIHIEL

"What are we going to do?" asked Bob.

"What can we do?" Ned returned.

"Let's go after him and bring him back!" exclaimed the excitable Bob.
"Maybe the Germans have him!"

"Then we'll not easily get him," said Jerry. "And, as a matter of
fact, we can't even try."

"Why not?" asked Ned.

"Because we can't leave. All furloughs have been stopped these last
three days. We may go into action any minute. If the professor is in
trouble we can't help him."

"That seems hard," murmured Bob.

"It is," agreed Jerry. "But it's the fortune of war. We're here to
fight, and we've got to do that when the time comes. It may be that
the professor has only wandered off among our own soldiers, or those
of the French or English, after a butterfly or some other bug."

"But without his hat!" exclaimed Bob.

"And gone more than a day!" added Ned.

"Those things wouldn't worry him," said Jerry. "Half the time he
forgets his hat, and it is midsummer now. As for being gone more than
a day, he's often spent longer than that chasing a single flea. He is
used to camping out, and he'll get along somehow. We'll just have to
let him go, that's all."

"I suppose so," agreed Ned; "but it's too bad."

It was, but there was nothing they could do. The professor might
wander into the enemy's territory and be captured, or he might come
safely back to the little French village.

"Though if he doesn't come back what are we to do with his things and
about Professor Petersen's nieces?" asked Ned.

"The best we can," advised Jerry.

"After the wa