It seemed at first quite still; but presently, when Adam's eye became accustomed to it, he could see that it moved as if trembling.

This at once recalled to Adam's mind the light quivering above the well-hole in the darkness of that inner room at Diana's Grove, Oolanga's awful shriek, and the hideous black face, now grown grey with terror, disappearing into the impenetrable gloom of the mysterious orifice.

Instinctively he laid his hand on his revolver, and stood up ready to protect his wife.

Then, seeing that nothing happened, and that the light and all outside the tower remained the same, he softly pulled the curtain over the window.
Sir Nathaniel switched on the light again, and in its comforting glow they began to talk freely..