Hiram Maxim's machine-gun tree chopping demo! 470 Bullets!

Hiram Stevens Maxim, born February 4, 1840, was a late 19th century rival to brilliant engineers like Thomas Edison and the Wright Brothers. His early inventions included a mousetrap and even an early aircraft which might have made his name and fortune, if it had flown.

In 1883 he patented a new fully automatic machine-gun. An invention inspired by direct personal experience. Maxim's eureka moment came while at rifle practice with friends at Savannah, Georgia. The thumping recoil from his rifle was giving him painful kicks in the shoulder and he was getting tired of doing all the reloading himself. It occurred to Maxim to use one problem to solve the other. Could the force of the recoil be used to reload the weapon automatically?

Back at the drawing board, Maxim found an ingenious way to do it.

The key components are the barrel and the bolt. When a cartridge is fired both are forced backwards by the recoil, then the barrel is pushed forwards again by a spring, flipping out the spent cartridge. Meanwhile, the bolt is pushed forwards by another spring, loading and firing the next shot. Thanks to recoil the gun loads and fires itself with no outside help.

Now Maxim was in the machine-gun business. Hiram moved to London and unleashed a sales-offensive that matched brilliant engineering with flamboyant public-relations. A series of high-profile publicity stunts spread the news of the machine-gun around the world. Power brokers from all nations were invited to fire the weapon for themselves and one story, above all, became part of Maxim folklore. He claimed that his machine-gun could chop down trees.

Former special forces machine gunner Bob Pedesta aims to put this claim to the test. Using a 1916 Vickers gun, a British Army variation on Hiram Maxim's design, capable of firing 450 rounds per minute, he will attempt to topple a mighty Scot's Pine.

Having selected a suitable tree, Bob marked the trunk with white paint to serve as a target. Firing only short bursts to avoid overheating the muzzle, he began picking away at the tree trunk. After only 470 rounds the tree toppled.

Maxim's machine-gun was so effective during World War I that the basic design is still in use today. Maxim has quite a number of patents to his name, see his WikiPedia page for details.

CREDITS: The National Geographic Channel "Inventions of War" documentary series.

The Ray Gun In Action

The US military has given the first public display of what it says is a revolutionary heat-ray weapon to repel enemies or disperse hostile crowds.

In accordance with the BBC, called the Active Denial System, it projects an invisible high energy beam that produces a sudden burning feeling.

Military officials, who say the gun is harmless, believe it could be used as a non-lethal way of making enemies surrender their weapons.

Officials said there was wide-ranging military interest in the technology.

How the heat-ray gun works

"This is a breakthrough technology that's going to give our forces a capability they don't now have," defence official Theodore Barna told Reuters news agency.

"We expect the services to add it to their tool kit. And that could happen as early as 2010."

'Blast from an oven'

The prototype weapon was demonstrated at the Moody Air Force Base in Georgia.

A beam was fired from a large rectangular dish mounted on a Humvee vehicle.

The beam has a reach of up to 500m (550 yds), much further than existing non-lethal weapons like rubber bullets.

It can penetrate clothes, suddenly heating up the skin of anyone in its path to 50C.

But it penetrates the skin only to a tiny depth - enough to cause discomfort but no lasting harm, according to the military.

A Reuters journalist who volunteered to be shot with the beam described the sensation as similar to a blast from a very hot oven - too painful to bear without diving for cover.

Crowd control

Military officials said the weapon was one of the key technologies of the future.

"Non-lethal weapons are important for the escalation of force, especially in the environments our forces are operating in," said Marine Col Kirk Hymes, director of the development programme.

The weapon could potentially be used for dispersing hostile crowds in conflict zones such as Iraq or Afghanistan.

It would mean that troops could take effective steps to move people along without resorting to measures such as rubber bullets - bridging the gap between "shouting and shooting", Col Hymes said.

A similar "non-lethal" weapon, Silent Guardian, is being developed by US company Raytheon.