Quotation from: The Notebooks of Leonardo Da Vinci

Written by: Leonardo da Vinci

Note how aqua vitae absorbs into itself all the colours and smells
of flowers. If you want to make blue put iris flowers into it and
for red solanum berries (?)

639.

Salt may be made from human excrement burnt and calcined and made
into lees, and dried by a slow fire, and all dung in like manner
yields salt, and these salts when distilled are very pungent.