Two centuries ago, Nicéphore Niepce helped by Louis Daguerre invented the principle of "latent image" which is the basis of photography. Like Fleischmann and Pons, all their lives, Niepce, his brother and Daguerre tried to prove to the incredulous world the reality of their process. The first photographic images were taken under the Empire, in 1816, but Niepce and his brother died in poverty.
They also invented the first internal combustion engine, still under the reign of Napoleon the first. No one wanted to believe it, even though they had built a working prototype. Their engine, called "pyreolophore" propelled a boat. Even the English did not want to buy it to equip their warships. It was 150 years before ships gave up steam for diesel engines.
Their laboratory was located not far from where I live, on the Butte de Cormeilles which overlooks Paris. I see this hill when writing for you. Formerly, the Templars had dug a quarry there to extract gypsum. The city's high school bears the name of Louis Daguerre. Here is the statue of Daguerre in the grounds of the church. I photographed it in the last spring.
A beautiful statue of Daguerre has been erected in Washington, at the corner of 7th Street on Avenue C.
Photography did not take its industrial development until the 1840s. The world was not ready ...
But what is the principle of photography? Few remember it today, in the age of the digital image.
Photons of light or high energy particles create electron / hole pairs in silver iodide crystals. Crystals containing these metastable electron / hole pairs are more reactive than other crystals, and they react faster with the reducing agent. (Mercury vapor in the first Daguerreotype process, but atomic hydrogen also makes an excellent reducing agent.)
The pressure causes electric charges to appear by piezoelectric effect, and these charges create a latent image, which will be reduced by the developing agent (hydroquinone derivatives in the usual way, but vitamin C is also suitable)
The interaction between gelatin proteins and halide crystals is very important, and still poorly understood.
The factory that made gelatin for all the photographic film manufacturers in the world was in Saint-Denis, a blue collar town north of Paris where I was born. In summer, this factory spread a terrible smell in the city.
It was a cousin of Nicéphore Niepce, called Niepce de Saint-Victor, who discovered the action of radioactivity on photographic film. He published an article in the Comptes-Rendus de l'Académie des Sciences, (french PNAS) but his article was forgotten, because he was a photographer, and not a scientist, and it was Becquerel who rediscovered the radio-activity, many years after. (The word "radioactivity" was coined by Marie Curie)
I told you this story because the fate of Niepce is very similar to that of Martin Fleischmann.
But Nicephore Niepce was alone, and Fleischmann and Pons have disciples.