Nothing of value was added to this during the long stagnant period of the world called the middle ages, when the love of learning declined and men fell back into the old traditions, even to the extent of being taught by their priests that it was a sin to believe that the world was round. In those times the Arabs of Bagdad nourished knowledge more than any one else, but even they did little for geography. Finally the people of Europe began to wake up and look at things for themselves, instead of tamely accepting whatever the Pope of Rome or somebody else told them, and going and coming as he directed, regardless of whether it was for their interest to do so or not. One of the first and one of the most important influences of this revival in a desire for learning and the means for larger activity among men was the sudden extension of navigation; and this could not have come about, nor amounted to much, had the mariner’s compass not been invented.
“Off, thou Norseland Terror, clouding
Hellas with the jealous wraith
Which, the gods of old enshrouding,
Froze their hearts, the poet saith!”
Nothing is more obscure than the history of this instrument. The Chinese have certainly known, from a remote antiquity, that a magnetized needle, permitted to move freely, would turn north and south; but they seem to have profited as little by it as by so many other useful things that, long afterward, in the hands of the more energetic men of the West, contributed so largely to the progress of civilization. They were accustomed to poise a sliver of magnetized steel upon a bit of cork and set it afloat in a bowl of water. One end was marked, but this, with characteristic Chinese perversity, was the one pointing toward the south, not toward the north, as with us. This rude and simple arrangement is still in use among the Koreans—or was until recently. With such a contrivance and little, it any, knowledge of the variation of the needle, the Chinese of a thousand years ago made longer voyages than they have done in more modern times, trading not only with India, but sailing regularly as early at least as the ninth century to the Red Sea and the Persian Gulf.
There is no direct evidence, but it seems incontestable, that it was from these eastern mariners that the Arabs received the compass, and gradually brought it into use in their home waters, where it became well known to the crusaders and other sea-going travelers of the middle ages. Little reliance could be placed upon it, however, until the sixteenth century, when the need for something trustworthy for long voyages made men turn their attention to the study and betterment of it.
Toward the end of the fourteenth century, as I have said, Europe was beginning to recover from the terrible visitations of the plague, and to wake from its lethargy and to look abroad; and various influences were at work to promote exploration by sea and land—and what a grand field for study there was!
At this time nearly all the commerce of Europe, mainly in Italian hands, was with India and China. The overland route was long, perilous, and expensive, and that across the Arabian Gulf hardly less so. At best, such traffic was slow and limited, and the first need of the reviving world was the discovery of some straighter and quicker road to the East. In this quest Portugal came forward under the brilliant leadership of Dom Henrique (Prince Henry), styled “the Navigator,” who was the younger son of King João (or John) I, and half an Englishman, since his mother was Philippa of Lancaster. It was Prince Henry’s ambition to extend geographical discovery and improve seamanship, and he enlisted the help of the best navigators obtainable, regardless of nationality. In order to observe the heavens to better advantage, and also to study the tides and other nautical phenomena, he established an observatory on the bleak headland of Cape Sagres, where he willingly spent a large portion of his time for the sake of science. Navigation was sorely in need of such help. Except that they had rude compasses, of whose laws of variation, etc., they were ignorant, the seamen of that day were little, if any, better equipped than were those who sailed the “ships of Tarshish” a thousand years before that. Astronomers had supplied them with rough tables of the declination of the sun, pole-star, etc., by which, with the help of a cross-staff,—a simple instrument for ascertaining angles,—they might make a guess at the latitude. Longitude was found only by observations of eclipses of the moon, and noting the difference between the time when it was due at home, according to the almanac, and the local time of its actual coming; but at sea the “observations” were little better than guessing.