We find other accounts of the bottom of the sea and even of visits made to it, in the legendary writings of our period. Gervase of Tilbury[899] tells of an individual named Nicholas Pappas, a dweller on the shores of the Strait of Messina, who was forced by King Roger II of Sicily to dive into the waters. Being well known to the submarine monsters, he escaped all danger from molestation by them and afterwards used to tell about a grove beneath the “Strait of Pharo,” how the tides wash first one way and then the other through the branches of the trees, and how he had seen submarine mountains, valleys, fields and woods, and trees with acorns on them. Gervase adds that our faith in the truth of this story may be increased by noting the fact that acorns are often washed ashore along the neighboring coasts. Nicholas also used to occupy himself by warning ships of the approach of storms and showing sailors how to calm the waters with oil. At a later period the legend became current[900] of a man named “Piscis” or “The Fish” (possibly this should be substituted for the “Pappas” of Gervase) who was accustomed to swim under the Strait of Messina, having been sent there in the first place to rescue a chalice cast into the sea by King Roger. Alexander the Great, according to one version of the Romance of his adventures, also made a visit to the sea floor.[901] After he had crossed a desert infested with ferocious beasts, he called his companions together and complained that, in view of the fact that he had conquered the greater part of the world, he knew enough about the inhabitants of the land and now wanted to learn something of the inhabitants of the sea. He then proceeded to descend in a glass cask to the bottom of the deeps; there, among other things, he noted that the large fish eat the small ones, an observation whose novelty hardly seems to have justified the effort expended to make it. _THE WATERS OF THE LANDS_ Let us turn now to the waters of the lands—ground water, sources (wells, springs, fountains), rivers, and finally lakes. GROUND WATER