To complete the picture, one of the mechanical ape-men stood before the board as though expecting him. On the ape-man's head was a tight-fitting helmet, connecting with some part of the machine by a flexible tube. As Sherman entered the room the ape-man motioned him over to the board, pointed to the holes and in thick, but intelligible English, said "Watsch!" A flash of purple light appeared behind the first of the ground-glass screens. The ape-man promptly thrust his finger into the first of the holes. The light went out, and the ape-man turned to Sherman. "Do," he said. The light flashed on again, and Sherman, not unwilling to learn the purpose of the maneuver, did as his instructor had done. He was rewarded by a tearing pain in the finger-tip and withdrew the member at once. Right at the end it had become slightly grey. The ape-man smiled. Behind the second ground-glass a red light now appeared and the ape-man thrust his finger into another of the apertures, indicating that Sherman should imitate him. This time the aviator was more cautious, but as he delayed the light winked angrily. Again he received the jerk of pain in the finger-tip and withdrew it to find that the grey spot had spread. [Illustration: He was rewarded by a tearing pain in his fingertip. Behind the ground glass a red light now appeared.] When the third light flashed on he refused to copy the motion of his instructor. The light blinked at him insistently. He placed both hands behind his back and stepped away from the machine. The ape-man, looking at him with something like panic, beckoned him forward again. Sherman shook his head; the ape-man threw back his head and emitted a long, piercing howl. Almost immediately the door slid back and the car appeared. As Sherman stepped to its threshold, instead of admitting him, it thrust forth a gigantic folding claw which gripped him firmly around the waist and held him while a shaft of the painful yellow light was thrown into his eyes; then tossed him back on the floor and slammed shut vengefully. Dazed by the light and the fall, Herbert Sherman rolled on the floor, thoughts of retaliation flashing through his head. But he was no fool, and before he had even picked himself up, he realized that his present cast was hopeless. Gritting his teeth, he set himself to follow the ape-man's instructions, looking him over carefully to recognize him again in case--.