He spoke as much to himself as to the man who was now beside him. "It enters here," he said and peered downward toward the lead bulb. He placed a finger on the side of the metal. "About here, I should think.... Have you a drill? And a bit of quartz?"
The inventor's eyes were puzzled, but the assurance of his old instructor claimed obedience. He produced a small drill and a fragment like broken glass. And he started visibly as the one hand worked awkwardly to make a small hole in the side of the lead. But he withdrew his own restraining hand, and he watched in mystified silence while the quartz was fitted to make a tiny window and the thin figure stooped to sight as if aiming the opening toward a far corner where a brown rat sat upright in earnest munching of a dry crust.
The Professor drew Avery with him as he retreated noiselessly from the instrument. "Will you close the switch," he whispered.
The young man hesitated, bewildered, at this unexpected demonstration, and the Professor himself reached with his one hand for the black lever. Again the arc crashed into life, to hold for a brief instant until Professor Eddinger opened the switch.
"Well," demanded Avery, "what's all the show? Do you think you are teaching me anything—about my own instrument?" There was hurt pride and jealous resentment in his voice.
"See," said Professor Eddinger quietly. And his one thin hand pointed to a far shelf, where, in the shadow, was a huddle of brown fur and a bit of crust. It fell as they watched, and the "plop" of the soft body upon the floor sounded loud in the silent room.
"The law of compensation," said Professor Eddinger. "Two sides to the medal! Darkness and light—good and evil—life ... and death!"
The young man was stammering. "What do you mean?—a death ray evolved?" And: "What of it?" he demanded; "what of it? What's that got to do with it?"
"A death ray," the other agreed. "You have dreamed, Avery—one must in order to create—but it is only a dream. You dreamed of life—a fuller life—for the world, but you would have given them, as you have just seen, death."