Riemann's green is a green pigment ZnO.CoO, which is obtained by heating a mixture of zinc oxide and cobalt nitrate or by the reaction of cobalt nitrate with either 3Zn(OH)2ZnCO3 or zinc sulphate.

Aksionov used to drink a lot, was riotous, and was involved in illegal activities before his marriage

conceptualizing the truth,in hegel's term. A lot of philosophers(like descartes' three kinds of ideas) in his time (and a lot of mindfulness practitioners these days)believed a higher form of truth(or knowledge) exists which cannot be articulated but is to be intuited and felt.Hegel didnt consider this to be scientific.you can never know if your intuition is true or its just you making the stuff up.