The obvious question which the reader will ask is how could such craft possibly carry enough food for three years. The answer is that they did not even attempt such a feat. Instead, they used to make some harbour after part of their voyage was accomplished, land, sow their grain, wait till harvest-time, and then sail off with their food on board all ready for a further instalment of the journey. And there is really nothing too wonderful in this long voyage when we remember that in Africa what is to-day called Indian corn can be reaped six weeks after being sown; and that three years is not such an excessively long time for a well-manned craft fitted with mast and squaresail to coast from headland to headland, across all the bays and bights of the African continent. A great achievement it certainly was, not to be attempted (unless history is woefully silent) again until towards the close of the fifteenth century, when Vasco da Gama doubled the Cape of Good Hope. They had for years been wont in the Mediterranean to make voyages by night. They had steered their course by aid of the Polar star. “They undoubtedly,” remarks Professor Rawlinson, “from an ancient date made themselves charts of the seas which they frequented, calculated distances, and laid down the relative position of place to place. Strabo says that the Sidonians especially cultivated the arts of astronomy and arithmetic as being necessary for reckoning a ship’s course, and particularly needed in sailing by night.” Later on we shall again call attention to the great surprise which confronted the dwellers by the Mediterranean when they voyaged into other seas. The Phœnicians, so long as they cruised only in the former, had no tide to contend with; but when they set forth into the Red Sea, the Indian Ocean, the Atlantic, and the English Channel, they found a factor which, hitherto, they had not been compelled to encounter. But by such a seafaring race it was not long before even this new consideration was dealt with and utilised in the proper manner. “They noted,” says Rawlinson, “the occurrence of spring and neap tides, and were aware of the connection with the position of the sun and moon relatively to the earth, but they made the mistake of supposing that the spring tides were highest at the summer solstice, whereas they are really highest in December.”