The Seven Follies of Science [2nd ed.]

In the astronomy of the ancients as is generally known, the earth occupied the center of the universe and the list of planets included the sun and moon. After them came Mercury, Venus, Mars, Jupiter and Saturn. To the metal gold was given the name of Sol or the sun on account of its brightness and its power of resisting corroding agents hence the compounds of gold were known as solar compounds and solar medicines. As might have been expected, silver was assigned to Luna or the moon and in the modern pharmacopœia such terms as lunar caustic and lunar salts still have a place.