This is a google english translation of a german article that was published in December in 2021.
The Ultraviolet Enlightenment https://docs.google.com/document/d/178aIZp1ts5J1HCvWuZCkdoDvwbzp8tm_xiPGdonvPM8/edit?usp=sharing (The original article is here https://www.faz.net/aktuell/wissen/physik-mehr/entdeckung-des-uv-die-ultraviolette-erleuchtung-17687221.html ) It is about Goethe and Ritter in the early 1800s when Goethe encouraged Ritter to look for invisible radiation beyond the violet end of the spectrum given that Herschel had just discovered evidence of radiation below the red end of the spectrum using a thermometer. Ritter was eventually credited with the discovery of UV light using a light sensitive paper. However,as the article explains he did another experiment which was inspired by Goethe's concept of polarity but to this day the results have been dismissed as an error. Goethe predicted that if UV light darkened the photo chemical paper, then infrared light should lighten the same paper. Ritter reported finding this to be the case but because the chemical process is irreversible subsequent scientists have insisted that the _observation_ of lightning must have been an error. Until 2021 no one had even attempted to replicate this simple experiment, but now there is evidence that Ritter was probably correct in his observation. However, a mystery remains as to why the paper should be lightened. (one chemist speculates the silver atoms are being rearranged so their reflectivity changes). I am posting this as another example of how some observations can be prematurely rejected on the basis of opinion instead of a proper follow up investigation. In this case the observation is more than 200 years old! Harry
