(EXTRACT FROM THE NOTE-BOOK OF JOSEPH ROULETABILLE, continued)

“We separated on the thresholds of our rooms, with a melancholy shake of the hands. I was glad to have aroused in him a suspicion of error. His was an original brain, very intelligent but—without method. I did not go to bed. I awaited the coming of daylight and then went down to the front of the chateau, and made a detour, examining every trace of footsteps coming towards it or going from it. These, however, were so mixed and confusing that I could make nothing of them. Here I may make a remark,—I am not accustomed to attach an exaggerated importance to exterior signs left in the track of a crime.

“The method which traces the criminal by means of the tracks of his footsteps is altogether primitive. So many footprints are identical. However, in the disturbed state of my mind, I did go into the deserted court and did look at all the footprints I could find there, seeking for some indication, as a basis for reasoning.

“If I could but find a right starting-point! In despair I seated myself on a stone. For over an hour I busied myself with the common, ordinary work of a policeman. Like the least intelligent of detectives I went on blindly over the traces of footprints which told me just no more than they could.

“I came to the conclusion that I was a fool, lower in the scale of intelligence than even the police of the modern romancer. Novelists build mountains of stupidity out of a footprint on the sand, or from an impression of a hand on the wall. That’s the way innocent men are brought to prison. It might convince an examining magistrate or the head of a detective department, but it’s not proof. You writers forget that what the senses furnish is not proof. If I am taking cognisance of what is of............