ed south, avoiding certain cloud
masses, and had the gratification of seeing "the circus" swoop down from
the fleece in a well-designed encircling formation.

Tam swung round and made for Ypres, but again found a barring formation.

He turned again, this time straight for home, dropping his post-bag (he
had correctly addressed his letter and he knew it would be delivered),
shot down out of control a diving enemy machine that showed fight,
chased a slow "spotter" to earth, and flashed over the British trenches
less than two hundred feet from the ground with his wings shot to
ribbons--for the circus had got to within machine-gun range.

* * * * *

A week later Lieutenant von Mahl crossed the British lines at a height
of fifteen hundred feet, bombed a billet and a casualty clearing station
and dropped an insolent note addressed to "The Englishman Tamm." He did
not wait for an answer, which came at one o'clock on the following
morning--a noisy and a terrifying answer.

"This has ceased to be amusing," said Captain von Zeiglemann, emerging
from his bomb-proof shelter, and wired a requisition for three machines
to replace those "destroyed by enemy action," and approval for certain
measures of reprisal. "As for that pig-dog von Mahl...."

"He has received his fifth warning," said his unsmiling junior, "and he
is not happy."

Von Mahl was decidedly not happy. His commandant found him rather pale
and shaking, sitting in his room. He leaped up as von Zeiglemann
entered, clicked his heels and saluted. Without a word the commandant
took the letter from his hand and read:

If ye go to Germany A'll follow ye. If ye gae hame to yeer mither
A'll find the house and bomb ye. A'll never leave ye, McMahl.

TAM THE AVENGER.

"So!" was von Zeiglemann's comment.

"It is rascality! It is monstrous!" squeaked the lieutenant. "It is
against the rules of war! What shall I do, Herr Captain?"

"Go up and find Tam and shoot him," said Zeiglemann dryly. "It is a
simple matter."

"But--but--do you think--do you believe--?"

Zeiglemann nodded.

"I think he will keep his word. Do not forget, Herr Lieutenant, that Tam
brought down von Mueller, the greatest airman that the Fatherland ever
knew."

"Von Mueller!"

The young man's face went a shade paler. The story of von Mueller and his
feud with an "English" airman and of the disastrous sequel to that feud,
was common knowledge throug