The Dillon-Wagoner Graviton Polarity Generator, known colloquially as the spindizzy, is a fictitious anti-gravity device imagined by James Blish for his series Cities in Flight. This device grows more efficient with the amount of mass being lifted, which was used as the hook for the stories—it was more effective to lift entire cities than it was something smaller, such as a classic spaceship. This is taken to extremes in the final stories, in which an entire planet is used to cross the galaxy in a matter of hours using the spindizzy drive.
According to the stories, the spindizzy is based on principles contained in an equation coined by P.M.S. Blackett, a British physicist of the mid-20th century. Several other Blish stories involving novel space drives contain the same assertion. Blackett's original formula was an attempt to correlate the known magnetic fields of large rotating bodies, such as the Sun, Earth, and a star in Cygnus whose field had been measured indirectly. It was unusual in that it brought Isaac Newton's gravitational constant and Coulomb's constant together, the one governing forces between masses, the other governing forces between electric charges. However it was later disproved by more accurate measurements, not to mention new discoveries such as magnetic field reversals on Earth and the Sun, and the lack of a field on bodies such as Mars, despite its rotation being similar to Earth's.
Blish's extrapolation was that if rotation + mass produces magnetism via gravity, then rotation + magnetism could produce anti-gravity. The field created by a spindizzy is described as altering the magnetic moment of any atom within its influence.
The spindizzy was also used in at least two novels by Jesse Franklin Bone, The Lani People and Confederation Matador and appears as the nickname for fictional Heim Theory devices in Ken Macleod's The Execution Channel.