Now, in this history of his, Procopius mentions that, during the term of his prefecture at Constantinople, a great sea-monster was captured in the neighboring Propontis, or Sea of Marmora, after having destroyed vessels at intervals in those waters for a period of more than fifty years. A fact thus set down in substantial history cannot easily be gainsaid. Nor is there any reason it should be. Of what precise species this sea-monster was, is not mentioned. But as he destroyed ships, as well as for other reasons, he must have been a whale; and I am strongly inclined to think a sperm whale. And I will tell you why. For a long time I fancied that the sperm whale had been always unknown in the Mediterranean and the deep waters connecting with it. Even now I am certain that those seas are not, and perhaps never can be, in the present constitution of things, a place for his habitual gregarious resort. But further investigations have recently proved to me, that in modern times there have been isolated instances of the presence of the sperm whale in the Mediterranean. I am told, on good authority, that on the Barbary coast, a Commodore Davis of the British navy found the skeleton of a sperm whale. Now, as a vessel of war readily passes through the Dardanelles, hence a sperm whale could, by the same route, pass out of the Mediterranean into the Propontis.