The Right Chemistry: Reflections on the manufacture of mirrors (2022)

>"Von Liebig, already an established professor of chemistry at the University of Munich, was consulted by instrument maker Carl von Steinheill, who was attempting to improve the mirrors used in reflecting telescopes. Liebig went to work and discovered that coating glass with a mixture of ammonia, silver nitrate, sugar and a small amount of copper resulted in the deposition of a blemish-free surface of silver."

Fascinating!

The solution to the "How do you prevent mirrors from requiring Mercury?" (historical) problem...