He stood looking about him in some perplexity.
Adjoining the mosque, was a ruinous house, which clearly had had no occupants for many years. As Robert Cairn's gaze lighted upon its gaping window-frames and doorless porch, he seized his father by the arm.
"We might hide up there," he suggested, "and watch for anyone entering or leaving the place opposite."
"I have little doubt that this was the scene of my experience," replied Dr. Cairn; "therefore I think we will adopt your plan. Perhaps there is some means of egress at the back. It will be useful if we have to remain on the watch for any 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.