'Except for that, everything was in its place?' 'Yes, I think so.' 'Colonel Melrose, would you be so extremely obliging as to sit down in this chair a minute. I thank you. Now M. Ie docteur, will you kindly indicate to me the exact position of the dagger?' I did so, whilst the little man stood in the doorway.

'The hilt of the dagger was plainly visible from the door then. Both you and Parker could see it at once?' 'Yes.' Poirot went next to the window.

'The electric light was on, of course, when you discovered the body?' he asked over his shoulder.

I assented, and joined him where he was studying the marks on the windowsill.

'The rubber studs are the same pattern as those in Captain Paton's shoes,' he said quietly.

Then he came back once more to the middle of the room. His eye travelled round, searching everything in the room with a quick, trained glance.

'Are you a man of good observation. Doctor Sheppard?' he asked at last.

T think so,' I said, surprised.

'There was a fire in the grate, I see. When you broke the door down and found Mr Ackroyd dead, how was the fire? Was it low?' I gave a vexed laugh.

T -1 really can't say. I didn't notice. Perhaps Mr Raymond or Major Blunt ' The little man opposite me shook his head with a faint smile.

'One must always proceed with method. I made an error of judgment in asking you that question. To each man his own knowledge. You could tell me the details of the patient's appearance - nothing there would escape you. If I wanted information about the papers on that desk, Mr Raymond would have noticed anything there was to see. To find out about the fire, I must ask the man whose business it is to observe such things. You permit ' He moved swiftly to the fireplace and rang the bell.

After a lapse of a minute or two Parker appeared.

'The bell rang, sir,' he said hesitatingly.

'Come in, Parker,' said Colonel Melrose. 'This gentleman wants to ask you something.' Parker transferred a respectful attention to Poirot.

'Parker,' said the little man, 'when you broke down the door with Dr Sheppard last night, and found your master dead, what was the state of the fire?' Parker replied without a pause.

'It had burned very low, sir.' It was almost out.' 'Ah!' said Poirot. The exclamation sounded almost triumphant. He went on: 'Look round you, my good Parker. Is this room exactly as it was then?' The butler's eye swept round. It came to rest on the windows.

'The curtains were drawn, sir, and the electric light was on.' Poirot nodded approval.

'Anything else?' 'Yes, sir, this chair was drawn out a little more.' He indicated a big grandfather chair to the left of the door between it and the window. I append a plan of the room with the chair in question marked with an X.