“ Its shallowness and narrowness, its numerous islands and reefs, the shoal coasts of Prussia on the one side, and the rocky coast of Sweden on the other, make the navigation of the Baltic very dangerous. ”

“ The water of the Baltic is colder and clearer than that of the ocean, and contains only a fourth of the proportion of salt found in the Atlantic. Ice hinders the navigation of the Baltic from three to five months yearly. ”