Pasteur, Louis (1822-1895)
French chemist who studied the effect of tartaric acid on polarized light. Under a microscope in 1848, he discovered that there were two types of tartrate crystals which were mirror images of each other. This contradicted Mitscherlich who had observed only a single type of crystal. It was later found that Pasteur had serendipitously prepared his crystals in a particular way which would produce large crystals of both isomers. He separated the two types by hand, and, using a Nicol prism, noticed that they rotated the plane of polarization in opposite directions.…
