revolver, already loaded, was easily get-at-able, and the flap of his
hip-pocket unbuttoned: under the circumstances, he was not going to be
slow in producing that revolver in suggestive, if not precisely menacing
fashion. This done, he opened his box of chocolate, calculated its
resources, and ate a modest quantity. And while he ate, he looked about
him. In the morning light everything in his surroundings showed clearly
that his cursory inspection of the night before had been productive of
definite conclusions. There was no doubt whatever of the character of
the mysterious door set so solidly and closely in its framework in the
blank wall: the door of the strong room at Chestermarke's Bank was not
more suggestive of security.

He went over to the outer door when he had eaten his chocolate, and
examined that at his leisure. That, in lesser degree, was set into the
wall as strongly as the inner one. He saw no means of opening it from
the inside: it was evidently secured by a patent mechanical lock of
which Joseph Chestermarke presumably carried the one key. He turned from
it to look more closely at a shelf of books and papers which projected
from the wall above the table. Papers and books were all of a scientific
nature, most of them relating to experimental chemistry, some to
mechanics. He noticed that there were several books on poisons; his
glance fell from those books to various bottles and phials on the table,
fashioned of dark-coloured glass and three-cornered in shape, which he
supposed to contain poisonous solutions. So Joseph dabbled in
toxicology, did he? thought Neale--in that case, perhaps, there was
something in the theory which had been gaining ground during the last
twenty-four hours--that Hollis had been poisoned first and thrown into
the old lead-mine later on. And--what of the somebody, Horbury or
whoever it was, that lay behind that grim-looking door? Neale had never
heard a sound during the time which had elapsed before he dropped
asleep, never a faintest rustle since he had been awake again. Was it
possible that a dead man lay there--murdered?

A cheerful chirping and twittering in the space behind him caused him to
turn sharply away from the books and bottles. Then he saw that he was no
longer alone. Half a score sparrows, busy, bustling little bodies, had
come in by the open window, and were strutting about amongst the grey
ashes in front of the furnace.

Neale's glance suddenly fell on the loa