Eastern manufacture (Travels of Varthema, Introd. 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 in 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’amanière), 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. littéraire 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 beauté connoit et aperçoit.”
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 trésor, composed about 1260 (Livre i. pt. ii. ch. cxx.):—“Por ce nagent li marinier à l’enseigne des estoiles qui i sont, que il apelent tramontaines, et les gens qui sont en Europe et es parties decà nagent à la tramontaine de septentrion, et li autre nagent à cele de midi. Et qui n’en set la verité, praigne une pierre d’aimant, et troverez que ele a ij faces: l’une qui gist vers l’une tramontaine, et l’autre gist vers l’autre. Et à chascune des ij faces la pointe d’une aguille vers cele tramontaine à cui cele face gist. Et por ce seroient li marinier deceu se il ne se preissent garde” (p. 147, Paris edition, 1863). Dante (Paradiso, xii. 28-30) mentions the pointing of the magnetic needle toward the pole star. In Scandinavian records there is a reference to the nautical use of the magnet in the Hauksbók, the last edition of the Landnámabók (Book of the Colonization of Iceland):—“Floki, son of Vilgerd, instituted a great sacrifice, and consecrated three ravens which should show him the way (to Iceland); for at that time no men sailing the high seas had lodestones up in northern lands.”
Haukr Erlendsson, who wrote this paragraph about 1300, died in 1334; his edition was founded on material in two earlier works, that of Styrmir Karason (who died 1245), which is lost, and that of Hurla Thordson (died 1284) which has no such paragraph. All that is certain is a knowledge of the nautical use of the magnet at the end of the 13th century. From T. Torfaeus we learn that the compass, fitted into a box, was already in use among the Norwegians about the middle of the 13th century (Hist. rer. Norvegicarum, iv. c. 4, p. 345, Hafniae, 1711); and it is probable that the use of the magnet at sea was known in Scotland at or shortly subsequent to that time, though King Robert, in crossing from Arran to Carrick in 1306, as Barbour writing in 1375 informs us, “na nedill had na stane,” but steered by a fire on the shore. Roger Bacon (Opus majus and Opus minus, 1266–1267) was acquainted with the properties of the lodestone, and wrote that if set so that it can turn freely (swimming on water) it points toward the poles; but he stated that this was not due to the pole-star, but to the influence of the northern region of the heavens.
The earliest unquestionable description of a pivoted compass is that contained in the remarkable Epistola de magnete of Petrus Peregrinus de Maricourt, written at Lucera in 1269 to Sigerus de Foncaucourt. (First printed edition Augsburg, 1558. See also Bertelli in Boncompagni’s Bollettino di bibliografia, t. i., or S. P. Thompson in Proc. British Academy, vol. ii.) Of this work twenty-eight MSS. exist; seven of them being at Oxford. The first part of the epistle deals generally with magnetic attractions and repulsions, with the polarity of the stone, and with the supposed influence of the poles of the heavens upon the poles of the stone. In the second part Peregrinus describes first an improved floating compass with fiducial line, a circle graduated with 90 degrees to each quadrant, and provided with movable sights for taking bearings. He then describes a new compass with a needle thrust through a pivoted axis, placed in a box with transparent cover, cross index of brass or silver, divided circle, and an external “rule” or alhidade provided with a pair of sights. In the Leiden MS. of this work, which for long was erroneously ascribed to one Peter Adsiger, is a spurious passage, long believed to mention the variation of the compass.
- ↑ Adamas in India reperitur ... Ferrum occulta quadam natura ad se trahit. Acus ferrea postquam adamantem contigerit, ad stellam septentrionalem . . . semper convertitur, unde valde necessarius est navigantibus in mari.
- ↑ Sicut acus per naturam vertitur ad septentrionem dum sit tacta a magnete.—Sicut acus nautica dirigit marinarios in sua navigatione.
- ↑ Ginguené, Hist. lit. de l’Italie, t. i. p. 413.
