It seems a small thing, and yet it is a great one, which Goethe, as the above description shows, discovered almost by chance. This is shown by the conclusions to which he was led in the systematic prosecutions of his discovery. An account of them is given in his Beiträge zur Optik,⁶ published in 1791, the year in which Galvani came before the public with his observations in the sphere of electricity.