To give an idea of the scientific inquiry and sharp observation of mind in those days, I might cite Dante as a master exponent of nature study, and adept of science. Passing over his experiment in optics given in Paradiso, given so naturally as to justify the inference that investigation in physics was then not an uncommon mode of gaining knowledge, I call your attention to an observation made by Alexander Von Humboldt, the distinguished scientist, to prove that nothing escaped the eyes of Dante, intent equally upon natural phenomena and the things of the soul. Von Humboldt suggests that the rhetorical figure employed by Dante in his description of the River of Light with its banks of wonderful flowers (Par. XXX, 61) is an application of our poet's knowledge of the phosphorescence of the ocean. If you have ever looked down the side of a steamship at night as it ploughed its way forward, and if you have ever observed in the sea the thousand darting lights just below the water line your enjoyable experience will enable you to appreciate the beauty of this passage. I now quote: "I saw a glory like a stream flow by In brightness rushing and on either side Were banks that with spring's wondrous hues might vie And from that river living sparks did soar And sank on all sides in the flow'rets bloom Like precious rubies set in golden ore Then as if drunk with all the rich perfume Back to the wondrous torrent did they roll And as one sank another filled its room." Commenting on this passage, Von Humboldt says "It would seem as if this picture had its origin in the poet's recollection of that peculiar and rare phosphorescent condition of the ocean in which luminous points appear to rise from the breaking waves and, spreading themselves over the surface of the waters, convert the liquid plain into a moving sea of stars." This mention of a sea brings to mind the striking fact that Dean Church has pointed out, viz., when Dante speaks of the Mediterranean, he speaks not as a historian or an observer of its storms or its smiles but as a geologist. The Mediterranean is to him: "The greatest _valley_ in which water stretcheth." (Par. IX, 82.)