oud, "Beale knows about the Green Rust
and it can't be very long before I have to go to earth, but only for a
little time, my Hilda." He smiled, showing his white teeth, but it was
not a pleasant smile, "only for a little time, and then," he threw up
his arms, "we shall be rich beyond the dreams of Frankfurt."

"You will succeed, I know you will succeed, Julius," she breathed, "if I
could only help you! If you would only tell me what you are doing! What
is the Green Rust? Is it some wonderful new explosive?"

"Dry your face and go home," he said shortly, "you will find a detective
outside the door watching you, but I do not think he will follow you."

He dismissed the girl and followed her after an interval of time,
striding boldly past the shadow and gaining the cab-stand in Shaftesbury
Avenue without, so far as he could see, being followed. But he dismissed
the cab in the neighbourhood of Baker Street and continued his journey
on foot. He opened the little door leading into the yard but did not
follow the same direction as the girl had led Stanford Beale. It was
through another door that he entered the vault, which at one time had
been the innocent repository of bubbling life and was now the factory
where men worked diligently for the destruction of their fellows.

CHAPTER XXIV

THE GREEN RUST FACTORY

Stanford Beale spent a thoughtful three minutes in the darkness of the
cellar passage to which Hilda Glaum had led him and then he began a
careful search of his pockets. He carried a little silver cigar-lighter,
which had fortunately been charged with petrol that afternoon, and this
afforded him a beam of adequate means to take note of his surroundings.

The space between the two locked doors was ten feet, the width of the
passage three, the height about seven feet. The roof, as he had already
noted, was vaulted. Now he saw that along the centre ran a strip of
beading. There had evidently been an electric light installation here,
probably before the new owners took possession, for at intervals was a
socket for an electric bulb. The new occupants had covered these and the
rest of the wall with whitewash, and yet the beading and the electric
fittings looked comparatively new. One wall, that on his left as he had
come in, revealed nothing under his close inspection, but on the right
wall, midway between the two doors, there had been a notice painted in
white letters on a black background, and this showed fain