The fact was that Edgar Caswall was, if not mad, close to the border-line. Madness in its first stage—monomania—is a lack of proportion. So long as this is general, it is not always noticeable, for the uninspired onlooker is without the necessary means of comparison. But in monomania the errant faculty protrudes itself in a way that may not be denied. It puts aside, obscures, or takes the place of something else—just as the head of a pin placed before the centre of the iris will block out the whole scope of vision. The most usual form of monomania has commonly the same beginning as that from which Edgar Caswall suffered—an over-large idea of self-importance. Alienists, who study the matter exactly, probably know more of human vanity and its effects than do ordinary men. Caswall’s mental disturbance was not hard to identify. Every asylum is full of such cases—men and women, who, naturally selfish and egotistical, so appraise to themselves their own importance that every other circumstance in life becomes subservient to it. The disease supplies in itself the material for self-magnification. When the decadence attacks a nature naturally proud and selfish and vain, and lacking both the aptitude and habit of self-restraint, the development of the disease is more swift, and ranges to farther limits. It is such persons who become inbued with the idea that they have the attributes of the Almighty—even that they themselves are the Almighty.

Mimi had a suspicion—or rather, perhaps, an intuition—of the true state of things when she heard him speak, and at the same time noticed the abnormal flush on his face, and his rolling eyes. There was a certain want of fixedness of purpose which she had certainly not noticed before—a quick, spasmodic utterance which belongs rather to the insane than to those of intellectual equilibrium. She was a little frightened, not only by his thoughts, but by his staccato way of expressing them.

Caswall moved to the door leading to the turret stair by which the roof was reached, and spoke in a peremptory way, whose tone alone made her feel defiant.

“Come! I want you.”

She instinctively drew back—she was not accustomed to such words, more especially to such a tone. Her answer was indicative of a new contest.

“Why should I go? What for?”

He did not at once reply—another indication of his overwhelming egotism. She repeated her questions; habit reasserted itself, and he spoke without thinking the words which were in his heart.

“I want you, if you will be so good, to come with me to the turret roof. I am much interested in certain experiments with the kite, which would be, if not a pleasure, at least a novel experience to you. You would see something not easily seen otherwise.”

“I will come,” she answered simply; Edgar moved in the direction of the stair, she following close behind him.

She did not like to be left alone at such a height, in such a place, in the darkness, with a storm about to break. Of himself she had no fear; all that had been seemed to have passed away with her two victories over him in the struggle of wills. Moreover, the more recent apprehension—that of his madness—had also ceased. In the conversation of the last few minutes he seemed so rational, so clear, so unaggressive, that she no longer saw reason for doubt. So satisfied was she that even when he put out a hand to guide her to the steep, narrow stairway, she took it without thought in the most conventional way.