Al was thrown to the floor, half stunned by the shock.
In a few moments he had risen. The wall separating the two rooms was partially destroyed; the drawing room was in flames, there was no possibility of escape in that direction.
The boy rushed to the window and threw it open.
An exclamation burst from his lips; there was a fire escape outside.
He lifted the still unconscious girl in his arms, and a moment later he had begun the perilous descent of the frail iron ladder.
It was made in safety; in a few moments Al had deposited the girl in a carriage which had been in waiting for him.
By this time, early as was the hour, the street was thronged with people, attracted by the terrific explosion.
The upper part of the house was in flames, the fire escape was now crowded, and the half-dressed tenants of the building were rushing out, panic-stricken, from the various exits.
Al was fortunate enough to attract but little attention; five minutes later he and his sister were in a place of safety.
His sudden appearance on the scene may be briefly explained.