# The Mystery of the Yellow Room/Chapter 18

CHAPTER XVIII
Rouletabille Has Drawn a Circle between the Two Bumps on His Forehead
(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 château, 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 notproof. If I am taking cognisance of what is offered me by my senses I do so but to bring the results within the circle of my reason. That circle may be the most circumscribed, but if it is, it has this advantage—it holds nothing but the truth! Yes, I swear that I have never used the evidence of the senses but as servants to my reason. I have never permitted them to become my master. They have not made of me that monstrous thing,—worse than a blind man,—a man who sees falsely. And that is why I can triumph over your error and your merely animal intelligence, Frédéric Larsan.
"Be of good courage, then, friend Rouletabille; it is impossible that the incident of the inexplicable gallery should be outside the circle of your reason. You know that! Then have faith and take thought with yourself and forget not that you took hold of the right end when you drew that circle in your ​brain within which to unravel this mysterious play of circumstance.
"To it, once again! Go back to the gallery. Take your stand on your reason and rest there as Frédéric Larsan rests on his cane. You will then soon prove that the great Fred is nothing but a fool.—30th October. Noon.
"Joseph Rouletabille."
"I acted as I planned. With head on fire, I retraced my way to the gallery, and without having found anything more than I had seen on the previous night, the right hold I had taken of my reason drew me to something so important that I was obliged to cling to it to save myself from falling.
"Now for the strength and patience to find sensible traces to fit in with my thinking—and these must come within the circle I have drawn between the two bumps on my forehead!—30th of October. Midnight."
"Joseph Rouletabille."