curiosity which even the presence of the inspector could not restrain, "I haven't got any business to ask what all this machinery is for?"
"I was about to explain," Trant answered.
The psychologist rested his hands lightly on the plates upon the table; and, as he did so, a slight and, in fact, imperceptible current passed through him from the battery; but it was enough to slightly move the light reflected upon the screen.
"This apparatus," the psychologist continued, as he saw even Walker stare strangely at this result, "is the newest electric psychometer—or 'the soul machine,' as it is already becoming popularly known. It is made after the models of Dr. Peterson, of Columbia University, and of the Swiss psychologist Jung, of Zurich, and is probably the most delicate and efficient instrument there is for detecting and registering human emotion—such as anxiety, fear, and the sense of guilt. Like the galvanometer which you saw me use to catch Caylis, the Bronson murderer, in the first case where I worked with the police, Inspector Walker," the psychologist turned to his tall friend, "this psychometer—which is really an improved and much more spectacular galvanometer—is already in use by physicians to get the truth from patients when they don't want to tell it. No man can control the automatic reflexes which this apparatus was particularly designed to register when the subject is examined with his hands merely resting upon these two plates! As you see," he placed his hands in the test position again, "these are arranged so that the very slight current passing through my arms—so slight that I can-
