Replica of a »dry charging pile« designed by Johann Wilhelm Ritter (Ernst-Haeckel-Haus collection).

»A real heaven of knowledge on earth«

Romantic scientist Johann Wilhelm Ritter discovered UV radiation in Jena
Replica of a »dry charging pile« designed by Johann Wilhelm Ritter (Ernst-Haeckel-Haus collection).
Image: Jens Meyer (University of Jena)

While the poets of the Romantic era were busy exchanging ideas and opening up new intellectual spaces in their salons in Jena, the young researcher Johann Wilhelm Ritter was obsessing over the big questions of the time in his experiments. In doing so, he discovered UV radiation, laid the foundations for electrochemistry and invented the forerunner of today’s batteries 220 years ago.

By Sebastian Hollstein

»On 22 February, 12:30 pm, horn silver placed in the colour spectrum…«. This is the simple diary entry from the winter of 1801 in which Johann Wilhelm Ritter recorded an experiment that would lead to a scientific sensation. Experimenting in a darkened room, the young researcher refracted the light of the midday sun in a prism and directed the colour spectrum onto a sheet of white paper that was coated with a layer of silver chloride. The salt reacted with the light and turned particularly dark close to the violet end of the spectrum—where no coloured light could actually be seen. This is how Ritter—in Jena—first proved the existence of ultraviolet radiation, which is invisible to the human eye. His experiment was inspired by the astronomer Wilhelm Herschel, who had discovered infrared radiation one year earlier in a similar way, the only difference being that he had measured the temperature instead of observing a chemical reaction.

Johann Wilhelm Ritter, like hardly any other person, embodied the close unity that existed between the natural sciences and humanities around 1800. His research was driven by the search for an all-unifying principle. Jena’s Romanticists admired his ingenuity and insatiable thirst for discovery. He had a particularly close friendship with Novalis, who was quoted as saying: »Ritter is a knight and we are mere squires«. Clemens Brentano once described him as the »greatest man of our time«. Even great minds like Goethe paid the young researcher respect. The prince of poets wrote the following in a letter to Schiller: »It was just yesterday that I welcomed Ritter to my abode; he is a phenomenon to behold, a real heaven of knowledge on earth«. Ritter’s air of genius may have been reinforced by his living conditions. Novalis wrote about their first encounter in 1799: »At the time he was living in utter seclusion in a remote alley, consumed by a scantily furnished room, which he often did not escape for four weeks; ultimately because he knew of no reason why he should leave and, incidentally, for whom it would be worth the trouble.«

Fascinated by »animal electricity«

Born in the historical region of Silesia in 1776, Ritter enrolled at the University of Jena in April 1796 to study natural sciences. Having trained as a pharmacist’s apprentice and journeyman for five years, he instantly plunged into the seething cosmos of science at the »Alma Mater Jenensis«, developing an obsession for experimenting and quickly making a name for himself. As early as 1797, Alexander von Humboldt asked him to proofread his latest work and »record his shortcomings and overly one-sided arguments«. Humboldt’s work—like Ritter’s own first book (»Evidence that the Process of Life in the Animal Kingdom is Influenced by Constant Galvanism«), published in 1798—dealt with a question that electrified a large audience, even beyond the scientific community: Why do frogs’ legs twitch when they are between two metals?

This phenomenon had been accidentally observed in 1789 by the Italian doctor Luigi Galvani, who tried to explain it by postulating an »animal electricity« which could also be found, for example, in electric eels. The idea of a seemingly mysterious force in the body of living beings fell on fertile ground among the Romanticists, as reflected by the novel »Frankenstein« by the English writer Mary Shelley. However, this approach was criticized by Galvani’s compatriot Alessandro Volta, who attributed the electricity to metallic contact. Ritter, who had been experimenting in the contentious field of »galvanism« since the beginning of 1797, contradicted them by combining both ideas: He suggested that the voltage differences that generate the electric current were due to chemical reactions between the metal and the electrolyte (i.e. the frog’s legs). His investigations make him one of the founding fathers of electrochemistry.

Ritter’s charging pile as the forerunner of today’s batteries

Inspired by Volta, Ritter followed up with further experiments with electricity in 1802. He made a stack of copper plates and cardboard soaked in hydrochloric acid and conducted a voltage into the experimental set-up using a »voltaic pile«. He found that the material stored the charge, released the energy and could then be recharged. That’s why Ritter’s »charging pile« is seen as the forerunner of today’s batteries.

A celebrated scientist with a miserable existence

For all the success Ritter enjoyed in science, his living conditions were simply disastrous. His obsessive experimenting affected his health: He hardly slept, had a weakness for alcohol and didn’t shy away from experimenting on his own body during his research into galvanism. He even applied a voltage to his own eyes to observe the effects on his senses. To add to his misery, he was dogged by financial worries throughout his life. He ended his studies in 1798 and declared himself a private scholar. He was a welcome guest at the Thuringian courts between Gotha and Weimar, but he had no regular income. He was refused a lecturing position at the University of Jena, despite his appointment being demanded by students, because he had no academic degree to his name. That’s why, in 1805, Ritter moved with his wife and child from the university town in the Saale valley to Munich, where the Bavarian Academy of Sciences and Humanities had offered him a permanent position. However, the change of scenery hardly changed his way of life. Emaciated and heavily in debt, he died on 23 January 1810 at the age of 33.