About five o'clock, on a dull autumn afternoon, the cashier of one of
the largest banks in Paris was still at his desk, working by the light
of a lamp that had been lit for some time. In accordance with the use
and wont of commerce, the counting-house was in the darkest corner of
the low-ceiled and far from spacious mezzanine floor, and at the very
end of a passage lighted only by borrowed lights. The office doors
along this corridor, each with its label, gave the place the look of a
bath-house. At four o'clock the stolid porter had proclaimed,
according to his orders, "The bank is closed." And by this time the
departments were deserted, wives of the partners in the firm were
expecting their lovers; the two bankers dining with their mistresses.
Everything was in order.

The place where the strong boxes had been bedded in sheet-iron was
just behind the little sanctum, where the cashier was busy. Doubtless
he was balancing his books. The open front gave a glimpse of a safe of
hammered iron, so enormously heavy (thanks to the science of the
modern inventor) that burglars could not carry it away. The door only
opened at the pleasure of those who knew its password. The letter-lock
was a warden who kept its own secret and could not be bribed; the
mysterious word was an ingenious realization of the "Open sesame!" in
the _Arabian Nights_. But even this was as nothing. A man might discover
the password; but unless he knew the lock's final secret, the _ultima
ratio_ of this gold-guarding dragon of mechanical science, it
discharged a blunderbuss at his head.

The door of the room, the walls of the room, the shutters of the
windows in the room, the whole place, in fact, was lined with
sheet-iron a third of an inch in thickness, concealed behind the thin