It Is Said To Have Been Used In The Mediterranean Voyages At
The End Of The Thirteenth Or Beginning Of The Fourteenth Century.
With respect to the nations of the east, it is doubted whether they derived
their knowledge of it from the Europeans, or the Europeans from them.
When
we reflect on the long and perilous voyages of the Arabians, early in the
Christian era, we might be led to think that they could not be performed
without the assistance of the compass; but no mention of it, or allusion to
it, occurs in the account of any of their voyages; and we are expressly
informed by Nicolo di Conti, who sailed on board a native vessel in the
Indian seas, about the year 1420, that the Arabians had no compass, but
sailed by the stars of the southern pole; and that they knew how to measure
their elevation, as well as to keep their reckoning, by day and night, with
their distance from place to place. With respect to the Chinese, the point
in dispute is not so easily determined: it is generally imagined, that they
derived their knowledge of the compass from Europeans: but Lord Macartney,
certainly a competent judge, has assigned his reasons for believing that
the Chinese compass is original, and not borrowed, in a dissertation
annexed to Dr. Vincent's Periplus of the Erythrean Sea. At what period it
was first known among them, cannot be ascertained; they pretend that it was
known before the age of Confucius. That it was not brought from China to
Europe by Marco Polo, as some writers assert, is evident from the
circumstance that this traveller never mentions or alludes to it. The first
scientific account of the properties of the magnet, as applicable to the
mariner's compass, appears in a letter written by Peter Adsiger, in the
year 1269. This letter is preserved among the manuscripts of the university
of Leyden; extracts from it are given by Cavallo, in the second edition of
his Treatise on Magnetism. From these extracts it is evident that he was
acquainted with the attraction, repulsion, and polarity of the magnet, the
art of communicating those properties to iron, the variation of the
magnetic needle; and there are even some indications that he was acquainted
with the construction of the azimuth compass.
Next in importance and utility to the mariners' compass, in preparing the
way for the great discoveries by which the fifteenth century is
distinguished, maps and charts may be placed. For though, in general, they
were constructed on very imperfect and erroneous notions of the form of the
world, and the relative size and situation of different countries, yet
occasionally there appeared maps which corrected some long established
error, or supplied some new information; and even the errors of the maps,
in some cases, not improbably held out inducements or hopes, which would
not otherwise have been entertained and realized, as we have already
remarked, after D'Anville, that the greatest of Ptolemy's errors proved
eventually the efficient cause which led to the greatest discovery of the
moderns.
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