Chapter IX: Part II

Chap. I. He takes a round, or an ovoid magnet, and, after noting
its poles, files it between the two poles on both sides so that
it may be like a compressed sphere and thus occupy less space.
He then encloses this magnet between two light wooden capsules,
or boxes (_cassulas_) after the manner of a mirror ...
so fastened (with glue) that they cannot be opened and water
cannot enter. Then, says he, “place the capsules thus adjusted
in a large vessel full of water in which the two quarters of the
globe, viz. the South and the North, are found and marked, and
let them be indicated by a thread extending from the Northern to
the Southern part of the vessel; allow the capsules, or boxes,
to float and let there be above them a slender piece of wood in
the form (position) of a diameter. Then move this piece of wood
above the boxes until it is equidistant from the meridianal line
previously found and indicated by the thread, or is the same
(line) itself. This being done, according to the piece of wood
so situated, draw a line on the capsules, or boxes, and it will
be the perpetual meridianal line in all countries. That line,
therefore, when cut at right angles by another will be divided
in the centre and will be the line of the East and West. You
will thus have four quadrants actually marked on the capsules,
or boxes, representing the four quarters of the globe, of which
each will be divided into ninety, so that there may be in the
universe CCCLX parts (degrees) in the entire circumference of
the capsules, or boxes. Inscribe divisions on it as they were
formerly inscribed on the back of the astrolabe. There should
be, besides, a slender and light ruler above the capsules so
inscribed after the manner of the ruler on the back of the
astrolabe. Instead, however, of the sights (_pinnularum_),
should be erected at right angles two pins over the ends of the
ruler.”

This floating compass and the pivoted compass described
in the following chapter are to be found illustrated, pp.
67–77, figs. 10 and 12, at end of Part II of Bertelli
Barnabita’s Memoirs above referred to.

Chap. II. For the construction of a “better instrument and of
more certain effects” (the pivoted compass) he says: “Let there
be made a vessel of wood, brass or any other solid material
that you desire, and let it be turned in the shape of a jar
(_pixidis tornatum_) somewhat deep and tolerably large and
let a cover of transparent material, such as glass or crystal,
be fitted to it. If the whole vessel were of transparent
substance so much the better. Let there be placed in the centre
of the same vessel a slender axis of brass or silver, applying
its extremities to the two parts of the jar, that is to say (to
the) higher and lower. Let two holes be then made in the centre
of the axis facing each other at right angles. Then let a piece
of iron wire, like a needle, be passed through one of these
holes and another wire of silver or brass be passed through the
other, intersecting the iron at right angles. Let the cover at
first be divided into quadrants and each of the quadrants into
ninety parts, as was taught regarding the other instrument. Let
North and South and East and West be marked on it and let a rule
of transparent material be added to it with wires set upright at
the ends. You will approach what part of the magnet you please,
whether North or South, to the crystal until the needle moves
towards it and receives virtue from it. When this is done,
turn the vessel until one end (of the needle) stands directly
over the North in the instrument coinciding with the Northern
quarter of the sky. This being done, turn the rule to the sun,
by day, and to the stars, by night, in manner above indicated.
By means of this instrument, you will be enabled to direct your
footsteps to states and islands and to any places on the globe,
and wheresoever you may be, whether on land or on sea, so long
as their latitudes and longitudes are known to you.”

Chap. III. He constructs “a wheel which shall be constantly
in motion,” by making a very thin concave, silver case, after
the manner of a mirror, suitably perforated, around the rim
of which he inserts small iron nails, or teeth, bent closely
toward each other and which he then places upon an immovable
axis so that it may revolve easily.” He continues: “Let a silver
wire be added to this axis, fixed to it and placed between two
bowls on the end of which let a magnet be set, prepared in this
manner. Let it be rounded and its poles ascertained, as before
indicated; afterwards, let it be fashioned in the shape of an
egg with the poles intact, and let it be somewhat filed down
in two intermediate and opposite parts with the object of its
being compressed and occupying less space so that it may not
touch the inner walls ... let the magnet be placed on the wire
... and let the North pole be somewhat inclined towards the
small teeth of the wheel so that it may exercise its power ...
so that each tooth shall arrive at the North pole and, owing
to the impetus of the wheel, shall pass it by and approach the
Southern quarter. Thus every small tooth will be in a perpetual
state of attraction and avoidance. And, in order that the wheel
may perform its duty with greater rapidity, insert, between
the cases, a small round brass or silver pebble of such size
that it may be caught between any two of the small teeth, so
that, as one part of the wheel comes uppermost, the pebble may
fall to the opposite part. Wherefore, whilst the motion of the
wheel is perpetual on one side, the same will be in the case
of the pebble on the other side, or the fall of the pebble
caught between any two of the teeth will be perpetual to the
opposite side because as it is drawn towards the centre of the
earth by its weight, it assists the motion by not suffering the
small teeth to remain at rest in front of the stone. Let there
be spaces, however, between the small teeth conveniently curved,
so as to catch the pebble as it falls in the way the present
description indicates.”

Gilbert alludes to this perpetual-motion engine as having been devised or delineated by Peregrinus after he had got the idea from others (“De Magnete,” Book II. chap. xxxv.), and says that Jerome Cardan writes (“Opera,” Batav., 1663; “De Rerum Varietate,” Book, IX. chap. xlviii.) he could construct one out of iron and loadstone--not that he ever saw such a machine; that he merely offers the idea as an opinion and quotes from a report of the physician Antonio de Fantis of Treviso published in “Tabula generalis ac mare magnum scotice subtilitatis....”

In the “Magisterium Naturæ et Artis,” P. Francisci Tertii de Lanis, Brixiæ, 1684, Tractatus Tertius, Caput Secundum, p. 489, under Problema, I, _Motus perpetuus magnetis_, will be found allusion to the machines of (1) P. Peregrinus, as described in his epistle; (2) Taisnier; (3) Ant. de Fantis (cited by Cardan, as stated above); also mention of those of P. Schottus, Athan. Kircherus, Hieronimus Finugius and others; the most important of these being again alluded to throughout the third chapter of the same tract.

Gilbert makes further allusion to P. Peregrinus in his Book I. chap. i.; Book II. chap. xxxv.; Book III. chap. i.; Book IV. chap. i.; Book VI. chap. iv.

The Peregrinus’ Leyden manuscript (Fol. Cod. No. 227) already alluded to, Libri says (“Histoire des Sciences Mathém....” 1838, Vol. I. p. 383, note), is but a poor copy of the manuscript in the Paris Library (No. 7378A), from which latter the words _Petri ad Sygerum_ have been unfortunately transformed into _Petri Adsigerii_. He adds (Vol. II. pp. 70–71) that Humboldt cites (“Examen Critique,” p. 243) several authors who have alluded to the pretended Adsigerius. Mention is also made of the fact that W. Wenkebach, professor at the Hague Military School, examined the manuscripts in the Bodleian Library, Nos. 1629, 1794 and 2458, containing the treatise of Peregrinus, and that not one of them has the passage alluding to the declination. The Leyden manuscript, by the way, is said to be the only one, besides the Vatican copy, No. 5733, bearing the full date, which latter was first made known by Thévenot in his “Recueil de Voyages.” And it was a passage found in the Leyden manuscript (Q 27) which led to the belief that Peregrinus had first observed the variation or declination of the magnetic needle. The passage is as follows: “Take note that the magnet, as well as the needle that has been touched by it, does not point exactly to the poles, but that the part of it which is supposed to point to the South sometimes declines a little to the West, and that the part which looks towards the North sometimes inclines to the East. The exact quantity of this declination I have ascertained, after numerous experiments, to be five degrees. However, this declination is no obstacle to our guidance, because we make the needle itself decline from the true South by nearly one point and a half towards the West. A point contains five degrees.” This passage is unquestionably a late addition, being written in a different hand in a circle which itself is an incompleted outline of one of the figures of Peregrinus’ primitive compass.

REFERENCES.--“Encyclopædia Metropolitana,” Vol. III. p. 737
(“Bibliotheca Bibliothecarum,” fol. 11, p. 1400; “Catalogue
of the MSS. in the library of Geneva,” by Senebier, p. 207);
“Bulletino di bibliographia e di storia delle scienze ...” B.
Boncompagni, Vol. I. pp. 1–32, 65–99, 101–139, 319–420; Vol. IV.
pp. 257–288, 303–331; “Cat. bibl. publicæ univers. Lug. Bat.,”
p. 365; W. Wenkebach, “Sur Petrus Adsigerius ...” Rome, 1865
(taken from Vol. VII. No. 3 of the “Annali Pura ed Applicata”);
Brunet, “Manuel du Libraire,” 1863, Vol. IV. p. 493; “Br. Museum
Library,” 538, G 17; “Journal des Savants,” for April-May 1848,
and September 1870; Walker, “Magnetism,” 1866, p. 6; “English
Cyclopædia,” Vol. VIII. p. 160, also Dr. Hutton’s “Phil. and
Math. Dictionary”; Thos. Young, “A Course of Lectures on Nat.
Phil. and the Mechanical Arts,” London, 1807, Vol. I. pp. 746,
756; “Electro-magnetic Phenomena,” by T. A. Lyons, New York,
1901, Vol. I. pp. 105–106; Vol. II. p. 565 (with translation of
a portion of the original manuscript); “Examen Critique,” A. de
Humboldt, Paris, 1836, Vol. III. p. 31; “Science and Literature
of the Middle Ages,” Paul Lacroix, London, pp. 88–89, 280–282;
Silvanus P. Thompson, “Proceedings of the British Academy,”
1905–6, p. 377. It may be added that Houzeau et Lancaster,
“Bibl. Générale,” Vol. I. part i. p. 640, allude, at No. 3197,
to a manuscript of P. Peregrinus, “Nova compositio astrolabii
particularis,” as being in the Library of Geneva and as citing
the year 1261 in connection with the astronomical tables of John
Campan (Campanus, Italian mathematician, who died about 1300):
“Biog. Générale,” Vol. VIII. p. 373.

=A.D. 1270.=--Riccioli (Giovanni Battista), an Italian astronomer, member of the Society of Jesuits, _b._ 1598, _d._ 1671, asserts that at this period under the reign of St. Louis (1226–1270), French navigators were already using the magnetic needle, which they kept floating in a small vase of water, and which was supported by two tubes to prevent its falling to the bottom.

For a detailed account of the work of this well-known scientist consult: “Biographie Générale” Vol. XLII. pp. 147–149; Fabroni, “Vitæ Italorum,” Vol. II; Jean Baptiste Delambre, “Hist. de l’Astron. Mod.,” 1821; Davis, “The Chinese,” Vol. III. p. 11; Venanson, “Boussole,” pp. 70–71; Klaproth, “Boussole,” p. 54; Becquerel, “Résumé,” p. 59; Alex. Chalmers, “Gen. Biog. Dict.,” 1811, Vol. XXVI. pp. 182–183; Fischer, “Geschichte der Physik,” Vol. I; Tiraboschi, “Storia della letter. Ital.,” Vol. VIII; “English Cyclopædia,” Vol. V. pp. 76–77. Riccioli’s “Almagestum Novum,” Bologna, 1651, in two volumes, gives in book nine of the second volume the sentence of Galileo. This is the work which an old savant called “the pandects of astronomical knowledge” (Morhof Polyhistor, Vol. II. p. 347).

=A.D. 1271–1295.=--Polo (Marco), Paulum Venetum, is reported by many to have brought the compass from China to Italy. This is, however, supported by no evidence, nor is any allusion whatever made to the fact in the account he rendered of his voyage. Before Marco Polo set out on his travels, as Humboldt states, the Catalans had already made voyages “along the northern islands of Scotland as well as along the western shores of tropical Africa, while the Basques had ventured forth in search of the whale, and the Northmen had made their way to the Azores (the Bracir islands of Picignano).”

Polo relates that he set out from Acre in 1271, and returned to Venice “in the year 1295 of Christ’s Incarnation.” His “Travels” (“Il Milione di Messer Marco Polo”) according to the review of Col. Henry Yule, consists of a prologue and four books. It was dictated by him to a fellow prisoner, Rusticiano or Rusticello, of Pisa, and “it would appear now to be definitely settled that the original was ... of just such French as we might expect in the thirteenth century from a Tuscan amanuensis following the oral dictation of an Orientalized Venetian.”

Polo’s journeyings extended “so far to the north that he leaves the North Star behind him, and thence so far to the south that the North Star is never seen.”

REFERENCES.--Becquerel, “Elec. et Magn.,” Vol. I. p. 70;
Sonnini, in Buffon, “Minéraux,” Vol. VI. p. 84; Humboldt,
“Cosmos,” 1849, Vol. II. pp. 625, 656, or 1860, pp. 250–251;
“The Book of Ser Marco Polo,” by Sir Henry Yule, New York,
1903, which contains a very extensive bibliography at end of
the second volume; Libri, “Hist. des Sc. Mathém.,” Paris, 1838,
Vol. II. pp. 26, 140, etc.; D. A. Azuni, “Dissertation sur la
Boussole,” p. 69; Miller, “Hist. Phil. Ill.,” 1849, Vol. I. pp.
179–180; “Encycl. Brit.,” ninth ed., Vol. XIX. p. 407; “Journal
des Savants” for September 1818, also May 1823, and the five
articles published January to May 1867; see also “Centennaire
de Marco Polo,” par. H. Cordier, Paris, 1896, containing
“bibliographie très complète de toutes les éditions de Marco
Polo et des ouvrages qui lui sont consacrés.”

=A.D. 1282.=--Baïlak, native of Kibdjak, wrote this year, in Arabic, his book on “Stones,” wherein he says that he saw during his voyage from Tripoli to Alexandria, in 1242, the captains of the Syrian sea construct a compass in the following manner: “When the night is so dark as to conceal from view the stars which might direct their course according to the position of the four cardinal points, they take a basin full of water, which they shelter from wind by placing it in the interior of the vessel; they then drive a needle into a wooden peg or a corn-stalk, so as to form the shape of a cross, and throw it into the basin of water prepared for the purpose, on the surface of which it floats. They afterwards take a loadstone of sufficient size to fill the palm of the hand, or even smaller; bring it to the surface of the water, give to their hands a rotatory motion towards the right so that the needle turns on the water’s surface; they then suddenly and quickly withdraw their hands, when the two points of the needle face north and south. I have seen them, with my own eyes, do that during my voyage at sea from Tripolis to Alexandria.”

REFERENCES.--E. Salverte, “Phil. of Magic,” New York, 1847,
Vol. II. pp. 221–222, note; “American Journal of Science and
Arts,” Vol. XL. p. 247; Davis, “The Chinese,” Vol. III. p. xii;
Klaproth, “Lettre à M. de Humboldt,” pp. 59, 60, 67; Knight,
“Mech. Dict.,” Vol. II. pp. 1371 and 1397; “Electro-Magn.
Phenom.,” by T. A. Lyons, New York, 1901, Vol. II. p. 564.

=A.D. 1302.=--Gioia--Goia (Flavio or Joannes), an Italian pilot reported born at Positano, near Amalfi, is said by Flamnius Venanson (“De l’invention de la boussole nautique,” Naples, 1808, pp. 138 and 168) to be the real inventor of the mariner’s compass. This view is supported by Briet (Philippe), “Annales Mundi,” Vol. VI: Géog. et Hydrog., lib. x. cap. 8; by Voltaire (“Essai sur les Mœurs,” 1819, Vol. III. chap. cxli.), and by many others, but Klaproth (“Lettre ...” 1834, pp. 132–136) quotes Anthony of Bologna, called the Panormitan, as saying that Gioia lived in the fourteenth century and wrote both “_Prima dedit nautis usum magnetis Amalphis_” and “_Inventrix præclara fuit magnetis Amalphis_.” He adds that a statement to the same effect was made by Arrigi Brechmann in his “Historia Pandectarum Amalphitorum,” Dissertatio I, No. 22, Neapoli, 1735, p. 925, but that both are equally incorrect, for Gioja could not have invented an instrument which had already been in use more than a hundred years before his time.[19]

In his “Essay on Several Important Subjects,” London, 1676, Joseph Glanvill remarks (p. 33): “I think there is more acknowledgment due to the name of this obscure fellow, that hath scarce any left, than to a thousand Alexanders and Cæsars or to ten times the number of Aristotles and Aquinas’. And he really did more for the increase of knowledge and advantage of the world, by this one experiment, than the numerous _subtile disputers_ that have lived ever since the creation of the School of Wrangling.”

In the “Navigator’s Supply,” published 1597, William Barlowe speaks of “the lame tale of one Flavius at Amelphus in the Kingdome of Naples; for to have devised it (the compass) is of very slender probabilitie.”

M. D. A. Azuni says (“Boussole,” 1809, p. 144) that Gioja may have possibly invented the method of suspending the magnetic needle upon a perpendicular pivot so that it would remain horizontal whatever the movements of the vessel. This is very likely; at any rate, it must be admitted that this particular mode of support permits a freer movement to the needle in any direction and admits of more exact observations than when the needle is floating upon the water.

At pp. 487–505, Vol. II of his “Histoire des Sciences Mathématiques,” Guillaume Libri transcribes all he is able to from the almost illegible Peter Peregrinus’ manuscript, No. 7378A, in the Paris Bibliothèque, and refers to the imperfect mode of suspending the magnetic needle therein shown. It is, says he, similar to that spoken of by Francesco da Buti (Libri, Vol. II. pp. 67–68; Bertelli, “Pietro Peregrino,” pp. 63–66), who makes first mention of the compass in the Dante commentary (“Comment, sopra la Divina Commedia”) to be found in the collection of manuscripts No. 29, held by the Magliabechiana Library of Florence. He adds that the suspension of the needle is likewise alluded to by Guerino detto il Meschino, in a work first composed prior to the “Divina Commedia” (an Italian romance, attributed to one Andrew the Florentine) as _imbellico_, or _in bellico_, _in bilico_, meaning in suspense, throughout the editions of Padua, 1473, Bologna, 1475, Milan, 1482 and Venice, 1480, 1498. Mention is also made by Libri of the writings of Adélard de Bath on the compass, at p. 62 of his second volume.

REFERENCES.--Camillus Leonardus, “Speculum Lapidum”; the notes
at p. 180, Vol. I. of Dr. Geo. Miller’s “Hist. Phil. Ill.,”
London, 1849, Vol. I. p. 179, note; Venanson, “Boussole,”
pp. 158, 160; Knight, “Mech. Dict.,” Vol. II. p. 1398;
Collenutius--Collenuccio--“Compendio ... regno di Napoli,”
Venice, 1591; “Discussione della leggenda di Flavio Gioia,
inventore della bussola” (T. Bertelli, in “Rivista di Fisica
Mat. e Sc. Nat.,” Pavia, 1901, II. pp. 529–541); Matteo Camara,
“Memorie ... di Amalfi,” Salerno, 1876; “Literary Digest,” July
6, 1901, translated from “Le Cosmos,” Paris, June 8, 1901;
Giraldi, “Libellus de Re Nautica,” Bâle, 1540; Admiral Luigi
Fincati, “Il Magnete, la calamita e la bussola,” Rome, 1878;
“Annales de Géographie,” Vol. XI. No. 59, pp. 7–8 for September
15, 1902, and G. Grimaldi in the “Mem. d. Accad. Etrus. di
Cortona”; Paulus Jovius, “Historiarum,” Florence, 1552; Pietro
Napoli Signorelli, “Sull’invenzione della bussola nautica ...”;
M. A. Blondus, “De Ventis,” Venice, 1546; Cælius Calcagninus,
“Thesaurus Græcarum Antiquitatum,” 1697, Vol. XI. p. 761;
Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 149; “Riv. G.
Ital.,” X. 1903, pp. 1, 11, 105–122, 314–334.

For Briet (Philippe), _b._ 1601, _d._ 1668, see Michaud, “Biog. Univ.,” Paris, 1843, Vol. V. p. 527. The best, most complete edition of Briet’s “Annales Mundi” is the Venice, 1693.

=A.D. 1327–1377.=--It has been claimed by F. M. Arouet de Voltaire, who asserts it at Vol. III. pp. 251–252 of his “Essai sur les Mœurs et l’Esprit des Nations,” Paris, 1809, “that the first well-authenticated use of the compass” was made by the English during this period, which is that of the reign of King Edward III.

By Voltaire, the extraordinary (_prodigieuse_) antiquity of the Chinese is not questioned. They knew of the compass, but he says “it was not employed by them for its proper use, that of guiding vessels at sea. They travelled only along the shores. Possessed, as they were, of a country that furnished everything, they did not feel the need of going, as we do, to the other end of the world” (Vol. I. pp. 239, 247). Speaking of the Portuguese (Vol. III. p. 257) he says: “It was not before known if the magnetic needle would point to the south on approaching the South Pole; it was found to point constantly to the north during the year 1486.”

From the time of Edward III, the compass was known in England by the names of _adamant_, _sailing needle_ and _sail-stone dial_, as has been shown in the writings of Chaucer and others, the most important of which will be duly quoted in their order. The compass was alluded to, more particularly, by John Gower, “Confessio Amantis,”[20] Books I and VI; by Richard Hakluyt, “Voyages,” Vol. I. pp. 213, 215; and by Edward Fairfax, “Godefroy de Boulogne,” Book XV. s. 18.

It may be well to record here that Voltaire was “confessedly the foremost name, the acknowledged head of European literature of his time.” Goethe calls him “the greatest literary man of all time, the most astonishing creation of the Author of Nature” (“Nouvelle Biographie,” Vol. XLV. i. p. 445). Though not the first French author who wrote on the wonderful discoveries of Newton, he was the first to make them extensively known on the Continent.

REFERENCES.--Sir Harris Nicolas, “Hist. Roy. Navy,” 1847,
Vol. II. p. 180; Humboldt, “Cosmos,” 1859, Vol. V. p. 57,
note; Whewell, “Hist. of the Ind. Sc.,” 1859, Vol. I. p. 431;
“Crit. and Misc. Essays,” by Thomas Carlyle, Boston, 1860,
pp. 5–78. “La France Littéraire,” par Joseph M. Quérard,
Vol. X. Paris, 1839, pp. 276–457, devotes as many as 182
pages to bibliographical notices of Voltaire and names 1131
publications written by or relating to him, whilst in Quérard’s
“Bibliographie Voltairienne” will be found a still more extended
account at pp. i-xxxvi and at pp. 1–84.

THE MARINER’S COMPASS

Regarding the mariner’s compass, it can scarcely be doubted, from what precedes, that it came to the knowledge of Europeans in the manner indicated under the A.D. 1190 date.

Baïlik of Kibdjak--Baüak Kibdjaki--spoke of its use as generally well known by the Syrian navigators, who constructed it in exactly the same way as did the Chinese (A.D. 1111–1117 and A.D. 1282), and which resembled the compass seen by Brunetto Latini in the possession of Friar Bacon while in England prior to the year 1260 (Knight, “Mech. Dict.,” Vol. II. p. 1397).

Edrisi (Idrisi or Aldrisi), the most eminent of the Arabian geographers, is said by Boucher to have given a confirmed account of the polarity of the magnet, the early knowledge of which by the Arabs has been shown conclusively by Jacob de Vitry, Vincent de Beauvais and Albertus Magnus.

Signor P. T. Bertelli, who has been mentioned under the A.D. 1190 date, could not find any reference, however remote, to the directive property of the loadstone throughout a careful examination of Latin and Greek works dating from the sixth century B.C. to the tenth century A.D. He admits that the directive property was known to the Chinese, who had made rude floating needle compasses before the beginning of the Christian era, although these compasses are likely to have been brought home by the Amalfian sailors, who are, by some writers, represented as having substituted the pivoted needle as well as added the Rose of the Winds.[21] He will not, however, recognize the claims made in favour of Flavio Gioja. On the other hand, A. Botto has shown that the Amalfitans introduced the compass between the tenth and the eleventh centuries (“Contributo agli studi storici sull’origine della bussola nautica,” 1899). Consult likewise Vol. IX of “Annales de Géogr. et de Bibliogr.,” 1899, p. 8.

At p. 195 of the December 1904 issue of “Terrestrial Magnetism” is a short article relative to the claim made that the compass was invented by a Veronese named Salomone Ireneo Pacifico (A.D. 776–846) during the first half of the ninth century. It states that Bertelli considers this due to a misinterpretation of an inscription on Pacifico’s tomb, and it alludes to Bertelli’s previous paper on the subject in “Terrestr. Magn.,” Vol. VIII. No. 4, p. 179 (see also the number of “Terrestr. Magn.” for June 1905, p. 108, and the “Geographical Journal” for March 1905, pp. 334–335).

The earliest recorded use of the compass in a Spanish vessel, according to Capmany (“Memorias Historicas,” 1792), is to be found in the Chronicle of Don Pedro Niño, Conde de Buelna, as follows: “It is reported that Conde’s galleys left the island of La Alharina along the coast of Bombay ... and the pilots compared their needles which had been rubbed with the magnet stone....”

In Dr. Plumptre’s notes on Dante, reference is made to the fact that the European knowledge of the magnetic needle came from Arabia, and, like Humboldt, he quotes in support thereof an allusion from the Spanish “Leyes de las Partidas” belonging to the first half of the thirteenth century. The passage in the last named is spoken of by M. Fern de Navarrete in his “Discurso historico,” etc., 1802 (II. tit. ix. ley 28) and reads thus: “The needle which guides the seaman in the dark night and shows him, both in good and in bad weather, how to direct his course is the mediatrix (_medianera_) between the loadstone (_la piedra_) and the north star....” Humboldt adds: “See the passage in ‘Las siete Partidas del sabio Rey Don Alonso el IX’ [according to the usually adopted chronological order, Alfonso the tenth], Madrid, 1829, Vol. I. p. 473.”[22]

On the other hand, the knowledge of the compass by the Arabs in the thirteenth century has been most decidedly contested by E. Renaudot (“Anciennes Relations des Indes et de la Chine,” Paris, 1717, p. 3); by D. A. Azuni (“Dissertation sur l’origine de la Boussole,” Paris, 1809, pp. 102, 127); by Giovanni Battista Ramusio (“Coll. Voy.,” 1554, Vol. I. p. 379); by A. Collina (“Considerazioni,” etc., Faenza, 1748, p. 121, etc.). Buffon says (“Théorie de la Terre,” Paris, An. VIII. tome i. p. 300): “I know that some pretend the Arabs have invented the compass and have used it long before the French (see ‘Abrégé de l’histoire des Sarrazins,’ de Bergeron, p. 119) ... but that opinion always appeared to me devoid of reason; for there is no word in the Arabian, Turkish or Persian tongue which can be made to signify the compass.... They employ the Italian word _bossola_....”

The same view is entertained by Dr. William Robertson, principal of the University of Edinburgh, who, after announcing in his “History of the Reign of Charles V,” London, 1769, Vol. I. p. 78, that the mariner’s compass was invented soon after the close of the Holy War, gives at pp. 333–335 of his “Historical Disquisition,” London, 1812, a translation of the above passage taken from an early edition of that illustrious French naturalist George Louis Le Clerc, Comte de Buffon. Robertson adds: “This shows that the knowledge of this useful instrument was communicated to them (the Arabs) by the Europeans. There is not one single observation of ancient date made by the Arabians on the variation of the needle, or any instruction deduced from it for the assistance of navigators.... When Mr. Niehbuhr was at Cairo, he found a magnetic needle in the possession of a Mohammedan which served to point out the _Kaaba_, and gave it the name of _el magnetis_, a clear proof of its European origin.”

The claims of France to the discovery of the compass have been laid by some to the fact that the north point of the early instruments was generally drawn in the form of a _fleur de lys_, but Voltaire says (“Essai,” etc., Vol. III. p. 251), that the Italians drew this in honour of the sovereigns of Naples, a branch of the French royal family. The able writer in the English Cyclopædia (“Arts and Sciences,” Vol. III. p. 102) considers the design to be only “an _ornamented cross_ which originated in devotion to the mere symbol; though, as the compass undoubtedly came, he says, into Europe from the Arabs, the _fleur de lys_ might possibly be a modification of the _mouasala_, or dart, the name by which the Arabs called the needle” (“Phil. Mag.,” Vol. XVIII. p. 88).

REFERENCES.--Hallam, “Middle Ages,” Vol. III. chap. ix. part
ii.; Klaproth, “La Boussole,” pp. 53, 54 and 64–66; Davis, “The
Chinese,” Vol. III. p. 12; “Silliman’s Journal,” XL. 242–250;
“Nautical Magazine,” April 1903; “Ciel et Terre,” Juin 1,
1904, pp. 156–158; “Histoire de la Boussole,” par P. D. M.
Boddært; Libri, “Hist. des Sc. Mathém.,” Paris, 1838, Vol. I.
pp. 136–137, 382, etc.; Article “Bussola” in “Nuova Encycl.
Italiana,” by Bocardo, Vol. IV. Torino, 1877, p. 377, poesia
di Ugo di Sercy (Bercy) e di Giovanni di Mehun; “Harper’s
Magazine,” New York, for February, 1904; V. Molinier, “Notice
... boussole au xiii^e siècle,” Toulouse, 1850; G. Grimaldi,
“Dissert. ... della bussola,” Roma, 1741; McCulloch, “Traités
... boussole,” Paris, 1853; Magliozzi, “Notizie ... bussola,”
Napoli, 1849; Dr. Geo. Miller, “Hist. Phil. Illust.,” London,
1849, Vol. I. p. 180, note. For Edrisi, see “Journ. des
Savants,” issued in April and August 1843, and in December 1846.

=A.D. 1391.=--Chaucer (Geoffrey), the father of English poetry, thus expresses himself in “The Conclusions of the Astrolabie” (“English Poets,” London, 1810, Vol. I): “I haue giuen thee a sufficient astrolabye for oure orizont compowned after the latitude of Oxenforde.... Now hast thou here, the fower quarters of thin astrolabie, deuided after the fower principall plages or quarters of the firmament.... Now is thin Orisonte departed in XXIIII partiez by thi azymutz, in significacion of XXIIII partiez of the world; al be it, so that ship men rikne thilke partiez in XXXII.”

“Now maugre Juno, Aneas
For all her sleight and her compas
Atcheiued all his auenture.”

“House of Fame,” B. I.

“The stone was hard of adamaunt,
Whereof they made the foundemaunt,
The tour was round made in compas,
In all this world no richer was.”

“Rom. of the Rose.”

“Right as betwene adamants two
Of euen weight, a pece of yron set,
Ne hath no might to moue to ne fro
For what that one may hale, that other let.”

“Assem. of Foules.”

REFERENCES.--“English Poets,” London, 1810, Vol. I. p. 453; Ch.
Wells Moulton, “Library of Literary Criticism,” Vol. I. pp.
77–81.

=A.D. 1436.=--Bianco--Biancho--(Andrea), was an Italian cartographer living at Venice early in the fifteenth century, who published, in 1436, an atlas exhibiting charts of the magnetic variation. The knowledge of the latter, which is so indispensable to the correction of a ship’s reckoning, was then ascertained less by the sun’s rising and setting than by the polar star.

One of Bianco’s charts, now in the Biblioteca Marciana, Venice, shows two islands at the West of the Azores, leading many to believe that he possessed some knowledge of the existence of North and South America.

In Justin Winsor’s description of Dr. John G. Kohl’s collection of early maps (“Harvard Univ. Bulletin,” Vol. III. pp. 175–176), it is said that the original of Andrea Bianco’s Map of the World A.D. 1436, now at Venice, was reproduced by Joachim Lelewell (“Géographie du Moyen Age,” Pl. XXXII), and also in M. F. de Barros de Santarem’s “Essai sur l’histoire de la cosmographie et de la cartographie” (Pls. XXIII, XLIII).[23] Reference is also made thereto in Winsor’s “Bibliography of Ptolemy’s Geography,” sub anno 1478. Mr. Winsor adds: “Bianco’s views are of interest in early American cartography from the deductions which some have drawn from the configuration of the islands ‘Antillia’ and ‘De la man Satanaxio’--(two islands on its western verge)--that they represent Pre-Columbian discovery of South and North America.” Humboldt (“Crit. Untersuchungen,” I. 413, 416) has discussed the question, and pointed out that one island, “Antillia,” had earlier appeared on a map of 1425, and D’Avezac finds even earlier references to the same island.

To Andrea Bianco may be ascribed the best of all known forms of wind-roses. Admiral L. Fincati illustrates, in his well-known pamphlet “Il Magnete, la Calamita e la Bussola,” Rome, 1878, all the best-known examples from 1426 to 1612, those of Bianco having upon them either the _fleur de lys_ (referred to at A.D. 1327–1377) or the letter =T=[symbol], or designs of a triangle or trident, to indicate the north, whilst the east is designated by a cross, in same manner as shown in the 1426 Giraldi and the Oliva 1612–1613.[24]

For other forms and accounts of these rose-of-the-winds or compass cards, it would be well to consult more particularly Nordenskiöld, Nils Adolf Erik (1832–1901), “Periplus” (1897), as well as his “Facsimile Atlas” published eight years previously; Pedro de Medina, “Arte de Navegar”; Francesco Da Buti, “Comment, sopra la Div. Com.”; Simon Stevin’s “Haven-finding Art”; Athan. Kircher, “Magnes, sive de Arte Magnetica”; and Guillaume de Nautonniez, “Mécométrie de l’Eymant ... déclinaison guideymant pour tous les lieux ...” published 1602–1604.[25]

REFERENCES.--“Biog. Gen.,” Vol. V. pp. 922–923, Mazzuchelli,
“Scrittori d’ Italia”; “New Int. Encycl.,” New York, 1902–1903,
Vol. II. p. 796; Larousse, “Dict. Univ.,” Vol. II. p. 672;
Humboldt, “Cosmos,” 1859, Vol. V. p. 55; Johnson’s “New Univ.
Cycl.,” 1878, Vol. III. p. 230; “Der Atlas des Andrea Bianco
vom Jahre 1436 of Oscar Peschel,” Venedig, 1869; Justin Winsor,
“Narrative and Critical Hist. of America,” Boston, 1889, Vol. I.
pp. 50–56, 114, 117; “Formaleoni, saggio sulla nautica antica de
Veneziani,” Venez., 1783, pp. 51–59 (Libri, “Hist. des. Math.,”
Vol. III).

=A.D. 1490–1541.=--Paracelsus (Aureolus Theophrastus)--the assumed name of Philippus Aureolus Theophrastus Bombast von Hohenheim--a native of Switzerland, admitted by unprejudiced writers to have been one of the greatest chemists of his time (Hemmann, “Medico--Sur. Essays,” Berlin, 1778). The author of “Isis Unveiled” states that he made use of electro-magnetism three centuries before Prof. Oersted’s discovery, and that he rediscovered the occult properties of the magnet, “the bone of Horus,” which, twelve centuries before his time, had played such an important part in the theurgic mysteries, thus very naturally becoming the founder of the school of magnetism and of mediæval magico-theury. But Mesmer, who lived nearly three hundred years after him, and as a disciple of his school brought the magnetic wonders before the public, reaped the glory that was due to the fire-philosopher, while the great master died in want (“Isis Unveiled,” Vol. I. pp. 71, 72, 164).

Madame Blavatsky further adds (Vol. I. p. 167) that the full views of Paracelsus on the occult properties of the magnet are explained partially in his famous book “Archidoxorum,” wherein he describes the wonderful tincture, a medicine extracted from the magnet, and called “Magisterium Magnetis,” and partially in the “De Ente Dei” and “De Ente Astrorum,” lib. i.

It is now preserved in the Palace of the Genoese
Municipality.]

_Señor,--La soledad en que nos habeys desado non se puede
dezir. El libro de mys escrituras, di amiçer Françisco de
Ribarol, para que os le enbie, con otro traslado de cartas
mesajeras. Del recabdo y el lugar que porneys en ello, os pido
por merçed que lo escrivays aDon Diego. Otro tal se acabara, y
se os enbiara por la mesma guisa, y el mesmo miçer Françisco:
en ello fallereys escritura nueba. Sus Altezas me prometieron
de me dar todo lo que me pertençe y de poner [en] posesion de
todo aDon Diego como veyreys. Al Señor mi[çe]r Juan Luys y ala
Señora madona Catalina escrivo. La carta va con esta. Yo estoy
de partida en nonbre de la Santa Trinidad con el primer buen
tienpo, con mucho atabio. Si Geronimo de Santi Esteban viene
debeme esperar y no se enb[ali]jar con nada por que tomar[a]n
del lo que pudieren y despues le desaran en blanco. Venga aca y
el Rey y la Reyna le recibiran fasta que yo venga. Nuestro Señor
os aya en su santa guardia. Fecha a xxi de março en Sebilla
1502._

_Alo que mandardes,_

·_S_·

·_S· A ·S_·

_X M Y_

_X[-p]o FERENS._

Sir,--The loneliness in which you have left us cannot be told.
I have given the book of my writings to Messer Francesco di
Rivarola, in order that he may send it to you, with another
transcript of letters missive. Respecting the receipt thereof,
and the place in which you will put it, I beg you to be so
good as to write to Don Diego. Another similar one shall be
finished and sent to you in the same manner, and by the same
Messer Francesco; you will find a new writing in it. Their
Highnesses made me a promise to give me all that belongs to
me, and to put Don Diego into possession of everything, as you
will see. I am writing to Messer Gian Luigi and to the Signora
my Lady Caterina; the letter is going with this one. I am on
the point of setting out, in the name of the Holy Trinity, with
the first fine weather, with a great equipment. If Girolamo da
Santo-Stefano comes, he must wait for me, and not burden himself
with anything, because they will take from him whatever they
can, and will then leave him bare. Let him come hither, and the
King and Queen will receive him until I arrive. May Our Lord
have you in his holy keeping. Done on the 21st of March, in
Seville, 1502.

At your command

·S·

·S· A ·S·

X M Y

Xp̄o FERENS.]

Christopher Columbus. Translation of the letter written by
him to Nicolo Oderigo, shown opposite; made into English by
Mr. G. A. Barwick, B.A., of the British Museum. Permission to
reproduce both original letter and its translation was given
by Messrs. B. F. Stevens & Brown, London.]

In the words of Paracelsus, we give the following extracts concerning the loadstone, taken from “The Hermetic and Alchemical Writings ...” by A. E. Waite, London, 1894:

_Vol. I. p. 17._--“The adamant. A black crystal called ... Evax ... is dissolved in the blood of a goat.”

“The magnet. Is an iron stone, and so attracts iron to itself. Fortified by experience.... I affirm that the magnet ... not only attracts steel and iron, but also has the same power over the matter of all diseases in the whole body of man.”

_Vol. I. pp. 132_ and _145_.--“A magnet touched by mercury or anointed with mercurial oil, never afterwards attracts iron ... same if steeped in garlic....”

_Vol. I. p. 136._--“The life of the magnet is the spirit of iron which can be taken away by rectified _vinum ardens_ itself or by spirit of wine.”

_Vol. II. p. 59._--“Wherever the magnet has grown--there, a certain attractive power exists, just as colocynth is purgative and the poppy is anodyne....”

Mr. A. E. Waite says (Vol. II. p. 3) that the ten books of Paracelsus’ _Archidoxies_ stand in the same relation to Hermetic Medicine as the nine books _Concerning the Nature of Things_ stand to Hermetic Chemistry and to the science of metallic transmutation.

REFERENCES.--Biography of Paracelsus, in Larousse, “Dict
Univ.,” Vol. XII. pp. 171–172, in F. Hartmann, 1887, and in the
ninth ed. of the “Encycl. Brit.,” Vol. XVIII. pp. 234–236; Van
Swinden, “Recueil,” etc., La Haye, 1784, Vol. I. pp. 356–358;
Gilbert, “De Magnete,” Book I. chaps. i. and xiv., also Book
II. chap. xxv.; “Journal des Savants” for November 1849; Walton
and Cotton, “Complete Angler,” New York and London, 1847, pp.
212–213, for notes regarding Paracelsus, Robert Fludd, Jacob
Behmen and the Rosicrucians; “Dictionnaire Historique de la
Médecine,” N. F. Eloy, Mons, 1778, Vol. III. pp. 461–471;
“History and Heroes of the Art of Medicine,” J. Rutherfurd
Russell, London, 1861, pp. 157–175; “Histoire Philosophique de
la Médecine,” Etienne Tourtelle, Paris, An. XII. (1804) Vol. II.
pp. 326–346; “History of Magic,” Joseph Ennemoser, London, 1854,
Vol. II. pp. 229–241.

At p. 55 of the first supplement to “Select. Bibliog. of
Chemistry,” by H. C. Bolton, Washington, 1899, mention is made
of the Paracelsus Library belonging to the late E. Schuberth of
Frankfort-on-the-Main ... as containing 194 titles of works on
Paracelsus and 548 titles of works relating to Paracelsus and
his doctrines; the section on Alchemy embracing as many as 351
titles.

=A.D. 1492.=--Columbus, Colombo, Colon (Christopher), the discoverer of America., is the first to determine astronomically the position of a _line of no magnetic variation_ (on which the needle points to the true north) the merit of which discovery has, by Livio Sanuto, been erroneously attributed to Sebastian Cabot. (Livio Sanuto, “Geographia distincta in XII libri ...” wherein the whole of Book I is given to reported observations of the compass and to accounts of different navigators.)

Columbus did not, as many imagine, make the first observations of the existence of magnetic variation, for this is set down upon the charts of Andrea Bianco, but he was the first who remarked, on the 13th of September, 1492, that “2½ degrees east of the island of Corvo, in the Azores, the magnetic variation changed and passed from N.E. to N.W.” Washington Irving thus describes the discovery (“History ... Ch. Columbus,” Paris, 1829, Vol. I. p. 198): “On the 13th of September, in the evening, being about two hundred leagues from the island of Ferro (the smallest of the Canaries), Columbus, for the first time, noticed the variation of the needle, a phenomenon which had never before been remarked. He perceived, about nightfall, that the needle, instead of pointing to the North Star, varied about half a point, or between five and six degrees to the north-west, and still more on the following morning. Struck with this circumstance, he observed it attentively for three days and found that the variation increased as he advanced. He at first made no mention of this phenomenon, knowing how ready his people were to take alarm; but it soon attracted the attention of the pilots, and filled them with consternation. It seemed as if the laws of nature were changing as they advanced, and that they were entering into another world, subject to unknown influences (Las Casas, ‘Hist. Ind.,’ l. i. c. 6). They apprehended that the compass was about to lose its mysterious virtues; and, without that guide, what was to become of them in a vast and trackless ocean? Columbus tasked his science and ingenuity for reasons with which to allay their terrors. He told them that the direction of the needle was not to the polar star but to some fixed and invisible point. The variation, therefore, was not caused by any fallacy in the compass, but by the movement of the North Star itself, which, like the other heavenly bodies, had its changes and revolutions, and every day described a circle around the pole. The high opinion that the pilots entertained of Columbus as a profound astronomer gave weight to his theory, and their alarm subsided.”

Humboldt says: “We can, with much certainty, fix upon three places in the _Atlantic line of no declination_ for the 13th of September, 1492, the 21st of May, 1496 and the 16th of August, 1498.”

REFERENCES.--“Columbus and his Discoveries,” in the “Narrative
and Critical History of America,” by Justin Winsor, Boston,
1889, Vol. II. pp. 1–92; “Christopher Columbus, His life, work
...” by John Boyd Thacher, 1903; Giov. Bat. Ramusio, “Terzo
volume delle Navigationi e Viaggi ...” 1556; Dr. Geo. Miller,
“History Phil. Illust.,” London, 1849, Vol. II. pp. 216–219;
David Hume, “History of England,” London, 1822, Vol. III. pp.
387–398; Guillaume Libri, “Histoire des Sciences Mathématiques
en Italie,” Halle, 1865, Vol. III. pp. 68–85; “Columbus, a
Critical Study,” by Henry Vignaud, London, 1903; Weld, “Hist.
Royal Society,” Vol. II. p. 429; Thos. Browne, “Pseudodox.
Epid.,” 1658, Book II. pp. 68–69; Humboldt, “Cosmos,” 1849,
Vol. I. p. 174; Vol. II. pp. 636, 654–657, 671–672, and Vol.
V. (1859) pp. 55–56, 116; Knight, “Mech. Dict.,” Vol. II., pp.
1374, 1397; Poggendorff, “Geschichte der Physik,” Leipzig, 1879,
p. 270; “Raccolta di documenti e studi publicati della R. Com.
Columb. pel 40 Centenario alla scoperta dell’America,” Roma,
1892; Humboldt, “Examen Critique ... progrès de l’astronomie
nautique,” Paris, 1836, Vol. I. pp. 262–272, etc.

It may be worth noting here that the ashes of Columbus, removed from the Cathedral of Havana, were placed in a mausoleum at Seville, November 17, 1902 (“Science,” Dec. 12, 1902, p. 958).

Amongst the numerous claimants to the discovery of America, some have placed the great navigator Martin Behaim--Behem--(1430–1506), who received his instruction from the learned John Müller (Regiomontanus) and became one of the most learned geographers as well as the very best chart maker of his age. Cellarius, Riccioli and other writers assert that Behaim had, before Columbus, visited the American Continent, while Stuvenius shows, in his treatise “De vero novi orbis inventore,” that the islands of America and the strait of Magalhæns were accurately traced upon the very celebrated globe called the “World Apple” completed by Behaim in the year 1492, and which is still to be seen in Behaim’s native city of Nürnberg.[26] (See Mr. Otto’s letter to Dr. Franklin, in the second volume of the “Transactions of the American Philosophical Society held at Philadelphia for promoting useful knowledge,” likewise Humboldt, “Examen critique de l’histoire de la Géographie,” Vol. II. pp. 357–369; “The Reliquary,” London, Vol. VI. N.S. Jan.-Oct. 1892, pp. 215–229; Justin Winsor, “Narrative and Critical History of America,” Boston 1889, Vol. II. pp. 104–105; “Geogr. Jour.,” Vol. V. March 1895, p. 228.)

It was this same Martin Behaim (Humboldt, “Cosmos,” 1860, Vol. II. p. 255) who received a charge from King John II of Portugal to compute tables for the sun’s declination and to teach pilots how to “navigate by the altitudes of the sun and stars.” It cannot now be decided whether at the close of the fifteenth century the use of the log was known as a means of estimating the distance traversed while the direction is indicated by the compass; but it is certain that the distinguished voyager Francisco Antonio Pigafetta (1491–1534) the friend and companion of Magellan--Magalhæns--speaks of the log (_la catena a poppa_) as of a well-known means of measuring the course passed over. Nothing is to be found regarding way-measurers in the literature of the Middle Ages until we come to the period of several “books of nautical instruction,” written or printed by this same Pigafetta (“Trattato di Navigazione,” probably before 1530); by Francisco Falero, a brother of Ruy Falero, the astronomer (“Regimiento para observar la longitud en la mar,” 1535); by Pedro da Medina, of Seville (“Arte de Navegar,” 1545); by Martin Cortez, of Bujalaroz (“Breve Compendio de la esfera, y de la arte de navegar,” 1551), and by Andres Garcia de Cespedes (“Regimiento de Navigacion y Hidrografia,” 1606). From almost all these works--some of which, if not all, have naturally become very scarce--as well as from the “Summa de Geografia” which Martin Fernandez de Enciso had published in 1519, we learn most distinctly that the “distance sailed over” was then ascertained in Spanish and Portuguese ships not by any distinct measurement, but only through estimation of the eye, according to certain established principles. Medina says (lib. iii. caps. 11–12): “In order to know the course of the ship, as to the length of distance passed over, the pilot must set down in his register how much distance the vessel hath made according to hours (_i. e._ guided by the hour-glass, _ampoleta_); and, for this, he must know that the most a ship advances in an hour is four miles, and, with feebler breezes, three or only two.” Cespedes, in his “Regimiento” (pp. 99 and 156) calls this mode of proceeding _echar punto por fantasia_, and he justly remarks that if great errors are to be avoided, this _fantasia_ must depend on the pilot’s knowledge of the qualities of his ship. Columbus, Juan de la Cosa, Sebastian Cabot and Vasco da Gama, were not acquainted with the log and its mode of application, and they all estimated the ship’s speed merely by the eye, while they ascertained the distance they had made merely through the running down of the sand in the glasses known as _ampoletas_.

REFERENCES.--For F. A. Pigafetta, for Petro de Medina and for
Martin Cortez, Houzeau et Lancaster, “Bibl. Génér.,” Vol. I. pt.
ii. pp. 1221–1223; “New Gen. Biog. Dict.,” Jas. Rose, London,
1850, Vol. XI. p. 113; “Biog. Univ.” (Michaud), Vol. XXXIII. p.
297; “Grand Dict. Univ.” (Larousse), Vol. XII. p. 999; “Nouv
Biog. Gen.” (Hœfer), Vol. XL. p. 207. Also Dr. G. Hellmann’s
“Neudrucke,” 1898, No. 10, for reproduction of Francisco
Falero’s “Tratato del Esphera y del arte del marear” (Del
Nordestear de las Agujas), 1535, as well as for reproduction of
Martin Cortez’ “Breve Compendio” (De la piedra Yman), 1551.

=A.D. 1497.=--Gama (Vasco or Vasquez da), celebrated Portuguese navigator, is known positively to have made use of the compass during the voyage he undertook this year to the Indies. He says that he found the pilots of the Indian Ocean making ready use of the magnet. The first book of the history of Portugal by Jerome Osorius--wherein he gives (pp. 23–24, Book I. paragraph 15, 1581 ed.) a very extended “description de l’aiguille marine, invention des plus belles et utiles du monde”--states that, instead of a needle, they used a small magnetized iron plate, which was suspended like the needle of the Europeans, but which showed imperfectly the north.

Gilbert says (“De Magnete,” Book IV. chap. xiii.) that, as the Portuguese did not rightly understand the construction and use of the compass, some of their observations are untrustworthy and that in consequence various opinions exist relative to magnetic variation. For example, the Portuguese navigator Roderigues de Lazos--Lagos--takes it to be one-half point off the Island of St. Helena; the Dutch, in their nautical journal, make it one point there; Kendall, an expert English navigator, makes it only one-sixth of a point, using a true meridional compass. Diego Alfonso finds no variation at a point a little south-east of Cape das Agulhas,[27] and, by the astrolabe, shows that the compass points due north and south at Cape das Agulhas if it be of the Portuguese style, in which the variation is one-half point to the south-east.

REFERENCES.--Azuni, “Boussole,” p. 121; Klaproth, “Boussole,” p.
64; Knight, “Mech. Dict.,” Vol. II. p. 1398; Larousse, “Dict.,”
Vol. VIII. p. 977; “Voyageurs anciens et modernes” (Charton),
1855; “Le Comte Amiral D. Vasco da Gama,” par D. Maria T. da
Gama, Paris, 1902.

=A.D. 1497.=--Cabot (Sebastian), a prominent English navigator, lands, June 24, 1497, on the coast of Labrador, between 56 degrees and 58 degrees north latitude.

At p. 150 of the 1869 London edition of Mr. J. F. Nicholl’s “Life of Seb. Cabot” it is said the latter represented to the King of England that the variation of the compass was different in many places, and was not absolutely regulated by distance from any particular meridian; that he could point to a spot of no variation, and that those whom he had trained as seamen, as Richard Chancellor and Stephen Burrough, were particularly attentive to this problem, noting it at one time thrice within a short space.

REFERENCES.--Richard Hakluyt, “The Principal navigations,
voyages, traffiques and discoveries of the English nation,”
1599: at pp. 237–243, for the voyage of Richard Chancelor,
pilote maior, and, at p. 274, for “the voyage of Steuen
Burrough, master of the pinnesse called the Serchtrift”;
Livio Sanuto, “Geografia,” Venice, 1588, lib. i.; Fournier,
“Hydrographie,” lib. xi.; “Library of Am. Biog.,” by Jared
Sparks, Boston, 1839, Vols. II and VII as per Index at pp.
318–319; “Jean et Seb. Cabot,” par Hy. Harisse, Paris, 1882;
Geo. P. Winship, “The Cabot Bibliography,” London and New
York, 1900; Humboldt, “Examen Critique,” Vol. IV. p. 231, and
“Cosmos,” Vol. II. (1860) pp. 640, 657–658; Biddle, “Memoir of
Seb. Cabot,” 1831, pp. 52–61.

=A.D. 1502.=--Varthema-Vertomannus (Ludovico di) leaves Europe for the Indies, as mentioned at p. 25 of his “Travels,” translated by J. Winter Jones, London, 1863, from the original “Itenerario ... ne la India ...” Milano, 1523. He states that the Arabs who navigated the Red Sea were known to have long since made use of the mariner’s chart and compass, and he tells us, in the introduction and at p. 249, that “the captains carried the compass with the needle after our manner,” and that their chart was “marked with lines perpendicular and across.” When the polar star became invisible, they all asked the captain by what he could then steer them, and “he showed us four or five stars, among which there was one (_B. Hydrus_) which he said was opposite to (_contrario della_) our North Star, and that he sailed by the north because the magnet was adjusted and subjected to our north, _i. e._ because this compass was no doubt of European origin--its index pointing to the north, and being unlike that of the Chinese pointing to the south.”

REFERENCES.--Cavallo, “Magnetism,” London, 1787, Chap. IV;
also, “Hakluyt’s Collection of the early voyages, travels and
discoveries,” London, 1811, Vol. IV. p. 547, for “The navigation
and voyages of Lewes Vertomannus.”

=A.D. 1530–1542.=--Guillen (Felipe), an ingenious apothecary of Seville, and Alonzo de Santa Cruz (who was one of the instructors of mathematics to young Charles V, King of Spain and Emperor of Germany, and the _Cosmografo Mayor_ of the Royal Department of Charts at Seville), construct variation charts and variation compasses by which solar altitudes can be taken.

REFERENCES.--Humboldt, “Cosmos,” 1849, Vol. II. p. 658, and
1859, Vol. V. p. 56; L. A. Bauer, “U. S. Magn. Tables,” 1902, p.
26.

Although based upon very imperfect observations, the magnetic
charts thus devised by Alonzo de Santa Cruz antedate by more
than one hundred and fifty years the work of Dr. Halley (at
A.D. 1683).

=A.D. 1544.=--Hartmann (Georg) a vicar of the church of Saint Sebaldus, at Nuremberg, writes March 4, to the Duke Albrecht of Prussia, a letter which was brought to light by Moser and which reads as follows: “Besides, I find also this in the magnet, that it not only turns from the north and deflects to the east about nine degrees, more or less, as I have reported, but it points downward. This may be proved as follows: I make a needle a finger long, which stands horizontally on a pointed pivot, so that it nowhere inclines toward the earth, but stands horizontal on both sides; but, as soon as I stroke one of the ends (with the loadstone) it matters not which end it be, then the needle no longer stands horizontal, but points downward (_fällt unter sich_) some nine degrees, more or less. The reason why this happens I was not able to indicate to his Royal Majesty.” The above seems to establish the fact that Hartmann first observed the dip of the magnetic needle independently of Robert Norman.

Gilbert refers (“De Magnete,” Book I. chap. i.) to Fortunius Affaitatus--Affaydatus--an Italian physicist who, says he, has some rather silly philosophizing about the attraction of iron and of its turning to the poles, thus alluding to the latter’s small work called “Physicæ (et) ac astronomiæ (astronomicæ) considerationes,” which appeared at Venice in 1549. Nevertheless, it is a question whether Affaitatus was not actually the first to publish the declination of the magnetic needle. (“Biogr. Gén.,” Vol. I. p. 346; Mazzuchelli, “Scrittori d’Italia”; Bertelli, “Mem. sopra P. Peregrino,” p. 115; Adelung, Supplément à Jocher, “Allgem. Gelehrten-Lexicon”; Johann Lamont, “Handbuch des Magnetismus,” Leipzig, 1867, p. 425; J. C. Poggendorff, “Biogr.-Lit. Handwörterbuch,” Leipzig, 1863, Vol. I. p. 15; Michaud, “Biogr. Univ. Anc. et Mod.,” Vol. I. p. 208, Paris, 1843; Brunet, “Manuel,” Paris, 1860; “Biog. Cremonese de Lancetti”; M. le Dr. Hœfer, “Biog. Gen.,” Paris, 1852, Vol. I. p. 346.)

REFERENCES.--Dove, “Repertorium der Physik,” Vol. II, 1838, pp.
129–130; Poggendorff, “Geschichte der Physik,” 1879, p. 273; L.
Hulsius, “Descriptio et usus,” Nürnberg, 1597; “Ency. Brit.,”
1883, Vol. XV. p. 221; P. Volpicelli, “Intorno alle prime ...
magnete” (Atti dell Acad. Pont. de Nuov. Lincei, XIX. pp. 205,
210).

=A.D. 1555.=--Olaus Magnus, a native of Sweden and Archbishop of Upsala (where he died during 1568) issued in Rome his great work “Historia de Gentibus Septentrionalibus,” which, for a long time, remained the chief authority on Swedish matters. In this book, Gilbert says (“De Magnete,” lib. i. cap. 1) allusion is made to a certain magnetic island and to mountains in the north possessing such power of attraction that ships have to be constructed with wooden pegs so that as they sail by the magnetic cliffs there be no iron nails to draw out.

To this, reference is made by Thos. Browne (“Pseud. Epidem.,” 1658,