Harry Wethermill started.  Mr. Ricardo was at a loss.

“I had not followed my suggestion to its conclusion,” he admitted humbly.

“No,” said Hanaud.  “But I ask myself in sober earnest, ’Was there a seance held in the salon last night?’ Did the tambourine rattle in the darkness on the wall?”

“But if Helene Vauquier’s story is all untrue?” cried Wethermill, again in exasperation.

“Patience, my friend.  Her story was not all untrue.  I say there were brains behind this crime; yes, but brains, even the cleverest, would not have invented this queer, strange story of the seances and of Mme. de Montespan.  That is truth.  But yet, if there were a seance held, if the scrap of paper were spirit-writing in answer to some awkward question, why—­and here I come to my first question, which M. Ricardo has omitted—­why did Mlle. Celie dress herself with so much elegance last night?  What Vauquier said is true.  Her dress was not suited to a seance.  A light-coloured, rustling frock, which would be visible in a dim light, or even in the dark, which would certainly be heard at every movement she made, however lightly she stepped, and a big hat—­no no!  I tell you, gentlemen, we shall not get to the bottom of this mystery until we know why Mlle. Celie dressed herself as she did last night.”  “Yes,” Ricardo admitted.  “I overlooked that point.”  “Did she—­” Hanaud broke off and bowed to Wethermill with a grace and a respect which condoned his words.  “You must bear with me, my young friend, while I consider all these points.  Did she expect to join that night a lover—­a man with the brains to devise this crime?  But if so—­and here I come to the second question omitted from M. Ricardo’s list—­why, on the patch of grass outside the door of the salon, were the footsteps of the man and woman so carefully erased, and the footsteps of Mlle. Celie—­ those little footsteps so easily identified—­left for all the world to see and recognise?”

Ricardo felt like a child in the presence of his schoolmaster.  He was convicted of presumption.  He had set down his questions with the belief that they covered the ground.  And here were two of the utmost importance, not forgotten, but never even thought of.

“Did she go, before the murder, to join a lover?  Or after it?  At some time, you will remember, according to Vauquier’s story, she must have run upstairs to fetch her coat.  Was the murder committed during the interval when she was upstairs?  Was the salon dark when she came down again?  Did she run through it quickly, eagerly, noticing nothing amiss?  And, indeed, how should she notice anything if the salon were dark, and Mme. Dauvray’s body lay under the windows at the side?”

Ricardo leaned forward eagerly.

“That must be the truth,” he cried; and Wethermill’s voice broke hastily in: 

“It is not the truth and I will tell you why.  Celia Harland was to have married me this week.”