He looked the spectrograph over and decided that it was a fine piece of apparatus. So it wasn't the shining piece of commercial panel and gleaming meters. The high-frequency plumbing in it had the touch of a one-thumbed plumber's apprentice after ten days' drinking and the D plates were soldered together with a heavy hand. But it did work--and that's all he cared. The knobs and dials he had added were sticking out at all angles, but they functioned. And the line-voltage ripple present in the high-frequency generator made a particular mess out of the spectrograph separation. But electronic heaters do not normally come luxuriously equipped with rectifiers and filters so that the generator tubes were served with pure direct current--the circuit was self-rectified which would give a raucous signal if used as a radio transmitter. That generated a ripple-varied signal for the D plates and it screwed up the dispersion. The omission of refinement satisfied Thomas. So it wasn't perfect. It would be by the time Tom Lionel got through with it. And for the time being, Thomas would leave it alone. No use trying to make it work until Tom made an engineering model out of the physicist's experiment. Smiling to himself, Thomas went to work in the laboratory. He ignored Tom's experiments and started a few of his own accord. * * * * * Some hours later, the doorbell rang and Thomas went to the door to find a letter, addressed to Thomas Lionel, Ph.D. It was from an Arthur Hamilton, M.D. "Hm-m-m," said Thomas. "Is there something the matter with me?" He slit the envelope and removed a bill for consultation. "Consultation? Consultation? What in the name of all that's unholy is he consulting a doctor about? Or is the doctor consulting--no, the bill is rendered in the wrong direction. I know my consulting engineer." The physicist put on his hat and headed forth. It was not much later that he was sitting again in the same chair, facing Hamilton. "You're back." "Nope," smiled Thomas. "I'm here, not back." "But you were here last week." "That was another fellow. Look, Hamilton, I think I require your assistance. I have an engineer that is no end of bother." "Want to get rid of him, huh?" answered Hamilton. The suppressed smile fought valiantly and won, and the doctor's face beamed and then he broke into laughter. "What am I, anyway? Man, I can't take money from both sides. That's ... that's ... barratry, or something." "I'm the same man." "Nope. You are not." "Well, by and large, I thought it might be of interest to you to hear both sides. It might be that I am a useful citizen in spite of what the engineer says." "The engineer's opinion is that no physicist is worth an unprintable." "The physicist's opinion is that all engineers are frustrated physicists." "Might challenge him to a fight." "Have. But chess isn't too satisfying. I want blood." "It's your blood."