n the day which hides the sun, or through the darkness
of the night, they lose the knowledge of the quarter of the world to
which they are sailing, touch a needle with the magnet, which will turn
round till, on its motion ceasing, its point will be directed towards
the north" (W. Chappell, _Nature_, No. 346, June 15, 1876). The
magnetical needle, and its suspension on a stick or straw in water, are
clearly described in _La Bible Guiot_, a poem probably of the 13th
century, by Guiot de Provins, wherein we are told that through the
magnet (_la manette_ or _l'amaniere_), an ugly brown stone to which iron
turns of its own accord, mariners possess an art that cannot fail them.
A needle touched by it, and floated by a stick on water, turns its point
towards the pole-star, and a light being placed near the needle on dark
nights, the proper course is known (_Hist. litteraire de la France_,
tom. ix. p. 199; Barbazan, _Fabliaux_, tom. ii. p. 328). Cardinal
Jacques de Vitry, bishop of Acon in Palestine, in his _History_ (cap.
89), written about the year 1218, speaks of the magnetic needle as "most
necessary for such as sail the sea";[1] and another French crusader, his
contemporary, Vincent de Beauvais, states that the adamant (lodestone)
is found in Arabia, and mentions a method of using a needle magnetized
by it which is similar to that described by Kibdjaki. In 1248 Hugo de
Bercy notes a change in the construction of compasses, which are now
supported on two floats in a glass cup. From quotations given by Antonio
Capmany (_Questiones Criticas_) from the _De contemplatione_ of Raimon
Lull, of the date 1272, it appears that the latter was well acquainted
with the use of the magnet at sea;[2] and before the middle of the 13th
century Gauthier d'Espinois alludes to its polarity, as if generally
known, in the lines:--

"Tous autresi comme l'aimant decoit [detourne]
L'aiguillette par force de vertu,
A ma dame tor le mont [monde] retenue
Qui sa beaute connoit et apercoit."

Guido Guinizzelli, a poet of the same period, writes:--"In those parts
under the north are the mountains of lodestone, which give the virtue to
the air of attracting iron; but because it [the lodestone] is far off,
[it] wishes to have the help of a similar stone to make it [the virtue]
work, and to direct the needle towards the star."[3] Brunetto Latini
also makes reference to the compass in his encyclopaedia _Livres dou
tresor_, composed about 1260 (L