Gravity's Rainbow

by Thomas Pynchon

In the guidance, this is what happened: a little pendulum was kept centered by a magnetic field. During launch, pulling gs, the pendulum would swing aft, off center. It had a coil attached to it. When the coil moved through the magnetic field, electric current flowed in the coil. As the pendulum was pushed off center by the acceleration of launch, current would flow—the more acceleration, the more flow. So the Rocket, on its own side of the flight, sensed acceleration first. Men, tracking it, sensed position or distance first. To get to distance from acceleration, the Rocket had to integrate twice—needed a moving coil, transformers, electrolytic cell, bridge of diodes, one tetrode (an extra grid to screen away capacitive coupling inside the tube), an elaborate dance of design precautions to get to what human eyes saw first of all—the distance along the flight path.