Most lubricants are liquids. They keep the moving surfaces apart by hydrostatic pressure. But some, such as graphite and molybdenum disulphide, are solids. Their lamellar lattices have a very easy, low-friction slip-direction. Intriguingly, molybdenum disulphide works badly in moist air. At the contact-area of the moving surfaces, friction and compression heat the lubricant film; it reacts with water vapour to give molybdenum oxide and hydrogen sulphide. The reaction absorbs energy, which is drawn from the mechanism as added frictional loss.

Daedalus is now seeking the converse process. A lubricant which reacted under a roller to give out energy, would decrease the friction. Indeed, if the reaction were sufficiently energetic, the frictional loss would go negative. The lubricant would actually power the roller. DREADCO chemists are now developing this elegant and ultimately simple motor.

To generate propulsive power, the reaction must go with increase in volume. As the moving element rolls on a track lubricated with reagent, the rear of its contact-area would then be continuously ‘jacked up’ by reactive expansion, driving it along. Now metal oxidations run with vast expansion. Daedalus began to muse that a railway carriage ought to be propelled spontaneously by the thermally induced rusting of the track beneath its wheels — if rust were not such a bad lubricant. But graphite can also be expanded strongly, by the insertion of small molecules, including metal oxides, between its planes of carbon atoms. So DREADCO's ‘active lubricant’ will be a mixture of graphite and oxidizable metal dust. The transient heat of rolling contact will expand it strongly, thus accelerating the rolling.

Active lubrication will transform the design of small, low-powered mechanisms. They will run for ages on a modest supply of lubricant. Printers, cameras and innumerable office and domestic gadgets, will shed their motors, gear-trains and actuators, and be wonderfully quietened and simplified. More high-powered units will need special arrangements to replenish the lubricant and remove it when exhausted. Ultra-safe actively lubricated motors, free from heat and sparking, will colonize the fuel and chemical industries. An active road, pushing the cars along by reactive expansion beneath their tyres, is probably unfeasible. But an active skating rink should transform that energetic sport into a leisurely delight.