other's one—in itself an almost convincing figure—but the man with four did not even try to shoot his bad shell, while it appeared that the other had tried to shoot his bad one first. Now as there was not the slightest difference to the eye between the bad and good shells and—that which made it final—the duel was fought in the dark, the discrimination which one man had and your brother did not, could only have been an ability for fine discrimination in weight."
"I see!" Comprehension dawned curiously upon Sheppard's face.
"For the bullet and the case of those special shells of yours, Mr. Sheppard," the psychologist continued rapidly, "were so heavy—weighing together over three hundred grains, as I weighed them at your gun cabinet—and the smokeless powder you were trying was of such exceptional power that you had barely twenty grains in a cartridge; so the difference in weight between one of those full shells and an empty one was scarcely one-fifteenth—an extremely difficult difference for one without special deftness to detect in such delicate weights. It was entirely indistinguishable to you; and also apparently so to Mr. Chapin, though I was not at first convinced whether it was really so or not. However, as I have trained myself in laboratory work to fine differences—a man may work up to discriminations as fine as one-fortieth—I was able to make out this essential difference at once.
"This reduced my case to a single and extremely elementary consideration: could young Tyler have picked out those shells in the dark and shot Neal Sheppard with them. If he could, then I could take up the
