y considerable time."

They entered the ruined building and, by means of a rickety staircase,
gained the floor above. It moved beneath them unsafely, but from the
divan which occupied one end of the apartment an uninterrupted view of
the door below was obtainable.

"Stay here," said Dr. Cairn, "and watch, whilst I reconnoitre."

He descended the stairs again, to return in a minute or so and
announce that another street could be reached through the back of the
house. There and then they settled the plan of campaign. One at a time
they would go to the hotel for their meals, so that the door would
never be unwatched throughout the day. Dr. Cairn determined to make no
inquiries respecting the house, as this might put the enemy upon his
guard.

"We are in his own country, Rob," he said. "Here, we can trust no
one."

Thereupon they commenced their singular and self-imposed task. In
turn they went back to the hotel for breakfast, and watched
fruitlessly throughout the morning. They lunched in the same way, and
throughout the great midday heat sat hidden in the ruined building,
mounting guard over that iron-studded door. It was a dreary and
monotonous day, long to be remembered by both of them, and when the
hour of sunset drew nigh, and their vigil remained unrewarded, they
began to doubt the wisdom of their tactics. The street was but little
frequented; there was not the slightest chance of their presence being
discovered.

It was very quiet, too, so that no one could have approached unheard.
At the hotel they had learnt the cause of the explosion during the
night; an accident in the engine-room of a tramp steamer, which had
done considerable damage, but caused no bodily injury.

"We may hope to win yet," said Dr. Cairn, in speaking of the incident.
"It was the hand of God."

Silence had prevailed between them for a long time, and he was about
to propose that his son should go back to dinner, when the rare sound
of a footstep below checked the words upon his lips. Both craned their
necks to obtain a view of the pedestrian.

An old man stooping beneath the burden of years and resting much of
his weight upon a staff, came tottering into sight. The watchers
crouched back, breathless with excitement, as the newcomer paused
before the iron-studded door, and from beneath his cloak took out a
big key.

Inserting it into the lock, he swung open the door; it creaked upon
ancient hinges as it opened inward, revealing a gli