Uncle Elk was manifestly pleased by the chance to display his ingenuity.
“Let me explain several deductions of rather evident facts. At the right hand end of the upper shelf of books are four volumes: Fiske’s ‘Cosmic Philosophy’; James’ ‘Pragmatism’ and ‘Pluralistic Universe,’ and Henri Bergson’s ‘Creative Evolution.’ These books are a trifle out of alignment,—just enough so to show it was caused by some one else. Therefore he took them from their places. In returning the books to the shelf, he changed the places of Prof. James’ two works,—another proof if it were needed of the accuracy of my deduction. He must have stood exactly in front of that side of the book shelves, for on the floor to the right of such position are several short hairs, some black and some gray. They would not have fallen of themselves and must have been displaced by his fingers. They tell me his beard was grizzled or mixed and consequently he was in middle life.”
“Your explanation is based on the theory that he is right handed,” said the Scout Master; “are you not guessing there, Uncle Elk?”
“No; standing directly in front of the four volumes, the few threads of hair fell still further to the right. Their texture shows they came from his beard and not the crown of his head. They would not have fallen as they did unless they were displaced by the hand on that side of the man.”
“It seems to me,” continued the Scout Master, “that in so trifling a matter a person would make no distinction in the use of his hands. Besides, some persons are ambidextrous.”
“In certain circumstances he would use either hand, but the position of the outermost volume shows that it was shoved back by the same hand that loosened the two or three strands from his beard. When a man uses the same hand to do both of those things, it is good proof that he is right handed.”
“I am at a loss to understand how the position of the books shows that your visitor employed his right hand in restoring them to their places.” Uncle Elk’s eyes twinkled as he grew more subtle.
“You may think my explanation fine spun, but it is absolutely logical. It happens that ‘Pragmatism’ is the least interesting volume to me. I have not opened it for several weeks. A slight film of dust has gathered on the upper gilt edges. In withdrawing the book I rest my thumb against the upper part of the back and my first two fingers on the top; so every one does. Observe.”
Uncle Elk illustrated his words. With the book in his hand he shifted it about so that the sunlight was reflected from the bright yellow.
“There are the marks made by the first two fingers of a man’s hand, but the disturbance of the fine layer of dust clearly shows that the finger to the right was longer than the other. That is to say, it was the right hand: do I make myself clear?”