Teleforce

Teleforce is a proposed defensive weapon by Nikola Tesla that accelerated pellets or slugs of material to a high velocity inside a vacuum chamber via electrostatic repulsion and then fired them out of aimed nozzles at intended targets.

[5] The nozzle would send concentrated beams of particles through the free air, of such tremendous energy that they will bring down a fleet of 10,000 enemy airplanes at a distance of 200 miles from a defending nation's border and will cause armies to drop dead in their tracks.

All the energy of New York City (approximately two million horsepower) transformed into rays and projected twenty miles, could not kill a human being, because, according to a well known law of physics, it would disperse to such an extent as to be ineffectual.

My apparatus projects particles ..."[5] What set Tesla's proposal apart from the usual run of fantasy "death rays" was a unique vacuum chamber with one end open to the atmosphere.

[16] The idea of Tesla possibly having a new type of weapon and, further, his offer to give it to the League of Nations as a way to prevent future war were seen together as an alarming security threat by one US diplomat – a view not shared by his government.

[17] In 1935, the Soviet Union, through the US Amtorg Trading Corporation, an alleged[clarification needed] Soviet-arms front in New York City, paid Tesla $25,000 for detailed plans, specifications, and complete information on the method and apparatus, but it is unclear whether a physical device was ever produced.

[13] The United Kingdom considered Tesla's offer to sell the device to them for $30 million, maybe with the idea that even hinting they had a super weapon would be a deterrent to Adolf Hitler, but by 1938 they had dropped all interest.

[18] During this period, Tesla claimed that efforts had been made to steal the invention, saying that his room had been entered and that his papers had been scrutinized, but that the thieves or spies had left empty-handed.