Dudley watched her with fascinated eyes.  Apparently the space below was not very deep, for she had only disappeared as far as the knees down-ward, and then knelt down, and for a moment was lost to sight altogether.  She appeared to be struggling with something, and Dudley, consumed with horror, took a step back as he watched.

Presently she looked up.  Her face was in shadow, but he could see that she was panting, as if with some great exertion.

“Get back!  Stand in the middle of the room there, if you’re afraid,” said she, mockingly.  “Right out of my reach, mind, where I can’t get at you.”

Instinctively Dudley obeyed, stepping back into the little patch of light thrown by the candle.

He had scarcely reached the middle of the room when he felt the boards under his feet give way.  Staggering, he tried to retrace his steps, to reach the end of the room where the old woman, now again on a level with him, was watching him in silence.

But as he moved towards her she made a spring at him, and forcing him back with so much suddenness that he, quite unprepared, was unable to resist her attack, she flung him to the ground in the very middle of the room.

As he fell he felt the flooring give way under him.  The next moment he was struggling, like a rat in a well, in deep water.

CHAPTER XX.

THE PREY OF THE RIVER.

“Help!  Help!” shouted Dudley.  “Do you want to drown me?”

Great as the shock was of finding himself flung suddenly into what he supposed was a flooded cellar, Dudley did not at first believe that the old woman had any worse intention than that of playing him an ugly and malicious trick.

But as he uttered this question he looked up, and saw her face half a dozen feet above him, wearing an expression of fiendish malignity which froze his blood.

She was holding the candle so that she might see his face, and as he kept himself afloat in the small space available—­for he had no room to strike out, and no foothold on the slimy earthen sides—­he began to understand that she was in grim, deadly earnest, and that the place where the dead body of Edward Jacobs had been concealed was to be his own grave.

Then he did not cry out.  He saw that he would only be wasting his breath; that there was no mercy in the hard-light eyes, in the lines of the wicked, wrinkled mouth.

He made a struggle to climb up one side of the pit in which he found himself; but the soft earth, slimy with damp, slipped and gave way under him.  He tore out a hole with his fingers, then another, and another above that.  And all the while she watched him without a word, apparently without a movement.

But just as he came to a point in his ascent from which he might hope to make a spring for the top, she raised her thick stick and dealt him a blow on the head which sent him, with a splash and a gurgling cry, back into the water.