"Put on this gown and hood, over which I worked so hard, to copy from my own. Then we will slip back into the passage from the rear."
No sooner suggested than done; within another three minutes the two adventurers were picking their way cautiously along a roughly excavated subterranean passage. They cautiously ascended, as Haji led the way with sure steps. The Hindoo had made the most of his opportunities for study, and his knowledge of the labyrinth maze brought them soon to the main portal of the order.
Here he gave three knocks with clenched knuckles. The two hooded figures were in the view of the questioning eyes within.
Haji, imitated to the letter by Dr. Alden, gave the devil-worshipper's sign, fists clenched and pressed against the cheeks through the disguising masks and thumbs upturned like horns on either side of the head.
There was an instant's silent pause. Then a series of rhythmic knocks came from the opposite side of the big portal. Haji replied with seven knocks, repeated thrice.
Alden, mindful of his careful tutoring, did the same, stepping in front of the Hindoo to accomplish this necessary signal.
"What is the word, brother?" came a hoarse query from the cautious slit.
Alden leaned forward and whispered the Sanskrit phrase which he had memorized.
The door swung back on its hinges, and he entered.
He whipped the revolver from his pocket, and before the lone guardian of the order room realized what had happened, its muzzle was pressed against his heart.
Alden leaned forward to whisper hoarsely: "If you make one sound it will be your."  The man drew back, but Hall's wiry hands were gripping his arm. 