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 doors that opened onto the street. It had rained the night before and the rising sun drove red glints from the puddles on the sidewalk. Three robots, painted snow white to show they were night workers, pushed the doors open and came in. No one went out as the curfew hadn't ended yet. They milled around slowly talking in low voices. The only human being in the entire lobby was the night clerk dozing behind the counter. The clock over his head said five minutes to six. Shifting his glance from the clock, Jon became aware of a squat black robot waving to attract his attention. The powerful arms and compact build identified him as a member of the Diger family, one of the most numerous groups. He pushed through the crowd and clapped Jon on the back with a resounding clang. "Jon Venex! I knew it was you as soon as I saw you sticking up out of this crowd like a green tree trunk. I haven't seen you since the old days on Venus!" Jon didn't need to check the number stamped on the short one's scratched chestplate. Alec Diger had been his only close friend during those thirteen boring years at Orange Sea Camp. A good chess player and a whiz at Two-handed Handball, they had spent all their off time together. They shook hands, with the extra squeeze that means friendliness. "Alec, you beat-up little grease pot, what brings you to New York?"