Note Back to Main Text — Chapter IV · THE SEARCH FOR THE INDIES. EASTWARD OR PORTUGUESE ROUTE.

That time was after all not so long in arriving, for by the end of the thirteenth century the compass had come to be quite generally used,[376] and the direction of a ship's course could be watched continuously in foul and fair weather alike. For taking the sun's altitude rude astrolabes and jack-staffs were in use, very crazy affairs as compared with the modern quadrant, but sufficiently accurate to enable a Latitude and longitude. well-trained observer, in calculating his latitude, to get somewhere within two or three degrees of the truth. In calculating longitude the error was apt to be much greater, for in the absence of chronometers there were no accurate means for marking differences in time. It was necessary to depend upon the dead-reckoning, and the custom was first to sail due north or south to the parallel of the place of destination and then to turn at right angles and sail due east or west. Errors of eight or even ten degrees were not uncommon. Thus at the end of a long outward voyage the ship might find itself a hundred miles or more to the north or south, and six or seven hundred miles to the east or west, of the point at which it had been aimed. Under all these difficulties, the approximations made to correct sailing by the most skilful mariners were sometimes wonderful. Doubtless this very poverty of resources served to sharpen their watchful sagacity.[377] To sail the seas was in those days a task requiring high mental equipment; it was no work for your commonplace skipper. Human faculty was taxed to its utmost, and human courage has never been more grandly displayed than by the glorious sailors of the fifteenth and sixteenth centuries.