Born in 1880, Grindell-Matthews was educated at Bristol Merchant Venturers' College (England) and at nineteen volunteered for the Boer War, in which he was twice wounded. Trained as a research scientist, specialising in electricity, he was intrigued by the possibilities of radio telephony, then in its infancy, and as early as 1911, from Ely racecourse, Cardiff, he succeeded in conversing with the airman B C Hucks in a plane two miles away and travelling at 600 mph.
Grindell-Matthews, like many other inventors before and since, often failed to develop his ideas commercially. As soon as he had successfully solved a particular problem, his mind would leap ahead with a fresh idea.
Following the onset of World War I his experiments in developing a robot boat controlled by a light beam, using a new light-sensitive material, selenium, brought him quickly to the attention of the British Government. He proved his claims in trials at Portsmouth, using a larger steamship which was controlled by a naval searchlight more than five miles away.
The Government coughed up a first instalment of £25,000 on the proviso that Grindell-Matthews could further develop his device and produce an aerial torpedo as an answer to the Zeppelin -- but no more seems to have been heard of the idea.
After the war his probing mind went off in yet another direction -- the problem of talking film and in 1921 the inventor made a talkie of Sir Ernest Shackleton delivering his farewell speech before setting off for Antarctica.
In 1924 Grindell-Matthews really set the world a-buzz when newspapers got hold of the rumour that he had invented an invisible ray which would, as one report put it: 'Stop a motor working, kill plant life, destroy vermin, explode gunpowder, fire cartidges and light lamps.' Inevitably, invention and inventor were dubbed 'Death Ray' and the man himself quickly became the centre of fantastic public interest. Although he himself said: 'I knew I had at present little more than an interesting pea-shooter', the public wanted to believe that he had the ability to control armies, to make aircraft fall from the sky, in effect, the power to stop war.
It was the suggestion that the new device could cut out aircraft engines in flight that caused the Air Ministry to request an official test. Grindell-Matthews happily obliged, but the men from the Ministry were unimpressed, stating that all the inventor had demonstrated was that he could stop at will a small motorcycle engine from some fifteen yards -- no mean feat as it happens. Nevertheless, they were prepared to offer him £1,000 against further tests -- on a petrol engine that was to be provided by the Government.
The inventor declined however and announced shortly after that he was heading off the France. A Lyons company having made a 'princely offer' for his secret, which he now claimed could kill or disable men at a distance of four miles. He did fly to France but meanwhile his associates obtained a High Court injunction, preventing him selling the device.
Questions were asked in the House of Commons and one sceptical MP enquired whether it was true that a Ministry official had placed himself within ten yards of the ray, which was supposed to kill at a distance of several miles. A Government spokesman replied that it was true and added, amid laughter, that the official was doing well.
Whatever the truth about the ray's lethal properties, in July 1924, Grindell-Matthews announced he had lost the sight of his left eye as a result of his experiments. In that month he arrived in New York, thoroughly disgusted with the neglect he had suffered in Britain and doubts cast upon the validity of his experimental work. The following March he returned briefly to England to announce he had sold his death ray to the United States and was going to settle in that country.
No more was heard of the remarkable Welsh inventor until on Christmas Eve, 1930, when late shoppers in the Hampstead Heath area of London were startled to see a beam of light shoot up to the cloud base, about 6,000 ft up. The light continued to play on the cloud then took on the form of a rather voluptuous 'angel' with outstretched wings gliding across the sky. Traffic stopped and crowds gathered to gaze in awe at the sight. The angel vanished shortly after, only to be replaced by the words 'A Happy Christmas'. Grindell-Matthews was back.
He had been operating his latest invention from a pair of film location trucks and had already demonstrated his 'sky projector' in New York, by throwing a picture of the Stars and Stripes and the American eagle on to the clouds. 'The advantages of the machine in war time for conveying coded messages to airmen are obvious,' he pointed out. 'It also has many possibilities, for example, for electioneering purposes, for advertising, and also for announcing important items of news.'
Other demonstrations followed, including a huge glowing clock showing the correct time in the sky at Blackheath. But the sky projector proved to be yet another nine days' wonder and, once again, Grindell-Matthews was to drop out of the limelight.
He re-emerged five years later giving newspaper interviews from a bungalow-laboratory 1,500 feet up on Tor Cloud, a barren mountain in South Wales. Reporters told their readers how they, exclusively, had penetrated the ring of armed guards, barbed wire fences and secret-eye burglar alarms around the hideout, to learn how the inventor of the death-ray now planned to defend London from against any foreign attack.
This was to be accomplished by firing rockets to a height of 30,000 feet where, at that altitude, aerial torpedoes would release a brood of bombs suspended from parachutes by 500 feet of wire. Just how this was to be achieved is another matter but in July 1935, 'only a certain amount of experimental work remained to be done' and 'foreign governments, as well as the British, are eager for news of his work,' it was reported.
Two years later, in addition to his air defence scheme Grindell-Matthews was reportedly perfecting apparatus that would detect submarines thirty miles away. By 1939 he was 'only seeking new and more vital propellants' for his rockets. But by the time he died, aged sixty-one, during September 1941, in Clydach, Glamorgan, German bombers had repeatedly attacked London and other cities without any apparent hindrance from invisible rays or bombs suspended from sky hooks.
The inventor's personal life was shrouded in as much mystery as his work. In January 1938, he became the fifth husband of Madam Ganna Walska, a wealthy Polish opera singer of whom one unkind critic wrote: 'better seen than heard'. Madam Walksa was referred to by the newspapers as the '£25,000,000 bride' because of the fortunes of her four previous husbands.
While the evidence to back Grindell-Matthews' claims for his death ray and aerial torpedoes never really surfaced he was still an exceptional inventor. Talking films and such minor inventions as electronic burglar alarms and automatic street lighting can be attributed to his work.
A national newspaper after his death carried this simple notice: 'An electrical research worker who claimed to have invented a 'death ray', Mr Harry Grindell-Matthews, has left £522.'
By any standard Harry Grindell-Matthews was all that an eccentric scientist should be. Working in a remote laboratory in the Welsh mountains he claimed to have invented, among other things, an electronic beam which earned him the nickname 'Death Ray'.