In what year was the inventor of the Abbe prism born?
Abbe prism: In optics, an Abbe prism, named for its inventor, the German physicist Ernst Abbe, is a type of "constant deviation dispersive prism" similar to a Pellin–Broca prism. Ernst Abbe: Ernst Karl Abbe HonFRMS (23 January 1840 – 14 January 1905) was a German physicist, optical scientist, entrepreneur, and social reformer.
1840