to remain
unseen, and, to the best of his belief, gained an inclosed yard at the
back of Siddle's premises without having attracted attention. He slipped
the catch of a kitchen window only to discover that the sash was
fastened by screws also. The lock of the kitchen door yielded to
persuasion, but there were bolts above and below. A wire screen in a
larder window was impregnable. Short of cutting out a pane of glass, he
could not effect an entry on the ground floor.

Nimble as a squirrel, and risking everything, he climbed to the roof of
an outhouse, and tried a bedroom window. Here he succeeded. When the
catch was forced, there were no further obstacles. In he went, pausing
only to look around and see if any curious or alarmed eye was watching
him. He wondered why every back yard on that side of the high-street was
empty, not even a maid-servant or woman washing clothes being in sight,
but understood and grinned when the commotion Winter was creating came in
view from a front room.

Then he undertook a methodical search, working with a rapid yet
painstaking thoroughness which missed nothing. From a wardrobe he
selected an overcoat and pair of trousers which reeked with turpentine.
They were old and soiled garments, very different from the well-cut black
coat and waistcoat, with striped cloth trousers, worn daily by the
chemist. He drew a blank in the remainder of the upstairs rooms, which
included a sitting-room, though he devoted fully quarter of an hour to
reading the titles of Siddle's books.

A safe in the little dispensing closet at the back of the shop promised
sheer defiance until Furneaux saw a bunch of keys resting beside a
methylated spirit lamp.

"'Twas ever thus!" he cackled, lighting the lamp. "Heaven help us poor
detectives if it wasn't!"

In a word, since murder will out, Siddle had forgotten his keys!
Probably, he had gone to the safe for money, and, while writing the
notice as to his absence, had laid down the keys and omitted to pick
them up again.

Furneaux disregarded ledgers and account books. He examined a bank
pass-book and a check-book. In a drawer which contained these and a
quantity of gold he found a small, leather-bound book with a lock, which
no key on the bunch was tiny enough to fit. A bit of twisted wire soon
overcame this difficulty, and Furneaux began to read.

There were quaint diagrams, and surveyor's sketches, both in plan and
section, with curious notes, and occasional r