A sound of jarring iron was instantly audible behind the wall.  The solid hearthstone in front of the fire-place turned slowly at the feet of the two men, and disclosed a dark cavity below.  At the same moment, the strange and sickening combination of odours, hitherto associated with the vaults of the old palace and with the bed-chamber beneath, now floated up from the open recess, and filled the room.

The manager started back.  ‘Good God, Mr. Westwick!’ he exclaimed, ‘what does this mean?’

Remembering, not only what his brother Francis had felt in the room beneath, but what the experience of Agnes had been on the previous night, Henry was determined to be on his guard.  ‘I am as much surprised as you are,’ was his only reply.

‘Wait for me one moment, sir,’ said the manager.  ’I must stop the ladies and gentlemen outside from coming in.’

He hurried away—­not forgetting to close the door after him.  Henry opened the window, and waited there breathing the purer air.  Vague apprehensions of the next discovery to come, filled his mind for the first time.  He was doubly resolved, now, not to stir a step in the investigation without a witness.

The manager returned with a wax taper in his hand, which he lighted as soon as he entered the room.

‘We need fear no interruption now,’ he said.  ’Be so kind, Mr. Westwick, as to hold the light.  It is my business to find out what this extraordinary discovery means.’

Henry held the taper.  Looking into the cavity, by the dim and flickering light, they both detected a dark object at the bottom of it.  ‘I think I can reach the thing,’ the manager remarked, ’if I lie down, and put my hand into the hole.’

He knelt on the floor—­and hesitated.  ’Might I ask you, sir, to give me my gloves?’ he said.  ‘They are in my hat, on the chair behind you.’

Henry gave him the gloves.  ’I don’t know what I may be going to take hold of,’ the manager explained, smiling rather uneasily as he put on his right glove.

He stretched himself at full length on the floor, and passed his right arm into the cavity.  ‘I can’t say exactly what I have got hold of,’ he said.  ‘But I have got it.’

Half raising himself, he drew his hand out.

The next instant, he started to his feet with a shriek of terror.  A human head dropped from his nerveless grasp on the floor, and rolled to Henry’s feet.  It was the hideous head that Agnes had seen hovering above her, in the vision of the night!

The two men looked at each other, both struck speechless by the same emotion of horror.  The manager was the first to control himself.  ‘See to the door, for God’s sake!’ he said.  ’Some of the people outside may have heard me.’

Henry moved mechanically to the door.