David MacHeath watched a blue line wriggle its way erratically across the face of an oscilloscope. "The wave form is way off," he said flatly, "and the frequency is slithering all over the place."
He squinted at the line for a moment then spoke to the man standing nearby. "Signal Harry to back her off two degrees, then run her up slowly, ten minutes at a time."
The other man flickered the key on the side of the small carbide-Welsbach lamp. The shutters blinked, sending pulses of light down the length of the ten-foot diameter glass-walled tube in which the men were working. Far down the tube, MacHeath could see the answering flicker from Harry, a mile and a half away in the darkness.
MacHeath watched the screen again. After a few seconds, he said: "O.K.! Hold it!"
Again the lamp flashed.
"Well, it isn't perfect," MacHeath said, "but it's all we can do from here. We'll have to evacuate the tube to get her in perfect balance. Tell Harry to knock off for the day."
While the welcome message was being flashed, MacHeath shut off the testing instruments and disconnected them. It was possible to compensate a little for the testing equipment, but a telephone, or even an electric flashlight, would simply add to the burden.
Bill Griffin shoved down the key on the lamp he was holding and locked it into place. The shutters remained open, and the lamp shed a beam of white light along the shining walls of the cylindrical tube. "How much longer do you figure it'll take, Dave?" he asked.
"Another shift, at least," said MacHeath, picking up the compact, shielded instrument case. "You want to carry that mat?"