tle high
explosive, so little was necessary that it must escape notice unless you
knew what to search for. Yes, we caught him and he, the good fellow, the
good honest neutral"--it would be difficult to describe the bitterness
and scorn which rang through Marnier's words, "has been kind enough to
tell me how he earned his German pay as well as his French wages."

Hillyard leaned forward.

"Yes, tell me that!"

"On his way to the factory in the morning, he makes a call."

"Yes."

"The one on whom he calls fills the tube or has it just filled and gives
it to the workman. The time fuse is set for four hours and a half. The
workman has so arranged it that he will reach the factory half an hour
after the tube is filled. He passes the searcher. At his place he takes
off his waistcoat and hangs it up and in the pocket, just separated from
the explosive by the lining of the waistcoat, he places, secretly, the
tube. The tube has now four hours of life and the workman three and a
half hours of work. When the whistle goes to knock off for luncheon, the
workman leaves his waist coat still hanging up on the peg and goes out
in the stream. But half an hour afterwards, half-way through the hour of
luncheon, the acid reaches the explosive. There is a tiny explosion in
that empty hall, not enough to make a great noise, but quite enough to
start a big fire; and when the workmen return, the building is ablaze.
No lives are lost, but the factory is burnt down."

Hillyard sat for a little while in thought.

"Perhaps you can tell me," he said at length. "I hear nothing from
England or very little; and naturally. Are we obtaining Spanish workmen,
too, for our munition factories?"

"Yes."

It was clear now why B45 was especially suitable for this work. B45 was
Mario Escobar, a Spaniard himself.

"And filling the tubes! That is simple?"

"A child could do it," answered Marnier.

"Thank you," said Martin Hillyard.

The next evening he left Paris and travelling all night to Boulogne,
reached London in the early afternoon of the following day. Twenty
months had passed since he had set foot there.

CHAPTER XIX

UNDER GREY SKIES AGAIN

Hillyard landed in England athirst for grey skies. Could he have chosen
the season of the year which should greet him, he would have named
October. For the ceaseless bright blue of sea and heaven had set him
dreaming through many a month past, of still grey mornings sweet with
the smell of