d. xciv, and p. 249). We have already seen that the
Chinese as late as the end of the 18th century made voyages with
compasses on which but little reliance could be placed; and it may
perhaps be assumed that the compasses early used in the East were mostly
too imperfect to be of much assistance to navigators, and were therefore
often dispensed with on customary routes. The Arab traders in the Levant
certainly used a floating compass, as did the Italians before the
introduction of the pivoted needle; the magnetized piece of iron being
floated upon a small raft of cork or reeds in a bowl of water. The
Italian name of _calamita_, which still persists, for the magnet, and
which literally signifies a frog, is doubtless derived from this
practice.

The simple water-compass is said to have been used by the Coreans so
late as the middle of the 18th century; and Dr T. Smith, writing in the
_Philosophical Transactions_ for 1683-1684, says of the Turks (p. 439),
"They have no genius for Sea-voyages, and consequently are very raw and
unexperienced in the art of Navigation, scarce venturing to sail out of
sight of land. I speak of the natural _Turks_, who trade either into the
_black Sea_ or some part of the _Morea_, or between _Constantinople_ and
_Alexandria_, and not of the Pyrats of _Barbary_, who are for the most
part Renegado's, and learnt their skill in Christendom. ... The Turkish
compass consists but of 8 points, the four Cardinal and the four
Collateral." That the value of the compass was thus, even in the latter
part of the 17th century, so imperfectly recognized in the East may
serve to explain how in earlier times that instrument, long after the
first discovery of its properties, may have been generally neglected by
navigators.

The Arabic geographer, Edrisi, who lived about 1100, is said by Boucher
to give an account, though in a confused manner, of the polarity of the
magnet (Hallam, _Mid. Ages_, vol. iii. chap. 9, part 2); but the
earliest definite mention as yet known of the use of the mariner's
compass in the middle ages occurs in a treatise entitled _De
utensilibus_, written by Alexander Neckam in the 12th century. He speaks
there of a needle carried on board ship which, being placed on a pivot,
and allowed to take its own position of repose, shows mariners their
course when the polar star is hidden. In another work, _De naturis
rerum_, lib. ii. c. 89, he writes,--"Mariners at sea, when, through
cloudy weather i