except the few night workers. But there were ways of getting around the letter of a law that didn’t concern itself with a definition of visible light. Sliding aside some of the shielding around his atomic generator, Jon turned up the gain. As it began to run a little hot the heat waves streamed out⁠—visible to him as infrared rays. He finished reading the paper in the warm, clear light of his abdomen.

The thermocouple in the tip of his second finger left hand, he tested the temperature of his leg. It was soon cool enough to work on. The waterproof gasket stripped off easily, exposing the power leads, nerve wires and the weakened knee joint. The wires disconnected, Jon unscrewed the knee above the joint and carefully placed it on the shelf in front of him. With loving care he took the replacement part from his hip pouch. It was the product of toil, purchased with his savings from three months employment on the Jersey pig farm.

Jon was standing on one leg testing the new knee joint when the ceiling fluorescent flickered and came back on. Five-thirty already, he had just finished in time. A shot of oil on the new bearing completed the job; he stowed away the tools in the pouch and unlocked the door.

The unused elevator shaft acted as waste chute, he slipped his newspaper through a slot in the door as he went by. Keeping close to the wall, he picked his way carefully down the grease-stained stairs. He slowed his pace at the 17th floor as two other mechs turned in ahead of him. They were obviously butchers or meat-cutters; where the right hand should have been on each of them there stuck out a wicked, foot-long knife. As they approached the foot of the stairs they stopped to slip the knives into the plastic sheaths that were bolted to their chestplates. Jon followed them down the ramp into the lobby.

The room was filled to capacity with robots of all sizes, forms and colors. Jon Venex’s greater height enabled him to see over their heads to the glass