Abstract
One of the great and persistent technological dreams of science fiction has been the invention which would nullify or reverse the force of gravity. H. G. Wells in The First Men in the Moon did it in 1901 with Cavorite, a substance which shields objects behind it from gravitational lines of force. James Blish in the Cities in Flight series used the Spindizzy, a device which converts rotation and magnetism into gravity fields and forces. And, of course, "floaters", "null-g speeders" and "grav sleds" have abounded as techno-props in science fiction stories for many years.