It is almost impossible to class with any certainty the numerous Lake Stations of Switzerland. Some few certainly date from the Stone age, others from the transition period, between it and that of the early use of metals, or even from the Bronze age. As therefore they have been occupied at different times by different people, some of them having even been still in use in the time of the Romans, it is most difficult to fix with any precision the date to which belong the various objects mixed together beneath the deep waters of the lakes. We can only say that the nets differ very much in the size of the meshes, and the thickness of the rope used. Those found at Robenhausen are very like those in use in France at the present day. There has, in fact, been no advance in the art of making fishing-tackle since the remote days of the Lake Dwellers. We are ignorant of the mode of manufacture of prehistoric nets. Did the Lake Dwellers, as some archæologists are disposed to think, use a loom? Did they use shuttles and rollers such as are employed by the Esquimaux and Californians of the present day? It is impossible to say, but it is supposed that the bears’ teeth sharpened to a point, found in some stations, were used to tighten the meshes. These meshes were generally square, and each one was finished of with a knot of the same size at each intersection. The lead weights so indispensable to fishermen of the present day for sinking the nets, were represented in prehistoric times by stones. These stones, which are drilled or notched, are found in all the Lake Stations. The fragments of pottery pierced with a hole found at Schussenried, a Lake Station of the Stone age on the Feder-See (Wurtemburg), were probably used for the same purpose. In some of the Swiss Lake Stations have also been found pieces of wood and cork, pierced with one or more holes, which had certainly served as floats. Numerous stone implements of the most primitive forms, often of rock not native to the country, have been found in some of the islands of Greece, as well as in Corsica, Sardinia, Elba, and Sicily. These discoveries bear witness to the presence of man in these islands at a very remote antiquity, though no other traces of the existence of prehistoric human beings have as yet been found there. These men can only have reached the islands by way of the sea. Boats were the only means of communication between the Lake Dwellers of Switzerland and the mainland, and, as we have seen, the ancient Scandinavians hunted fish on the deep ocean. We must therefore admit that attempts at navigation were made in the very earliest days of humanity. Alan, impelled by necessity, or perhaps only by curiosity, was not afraid to launch his bark, first upon the rivers, and later upon the more formidable waves of the sea Illi robur et æs triplex Circa pectus erat, qui fragilem truci Commisit pelago ratem Primus.26