In the copy of Seneca"s tragedies, published at Venice in 1510, bought at Valladolid by Ferdinand Columbus in March, 1518, for 4 reals (plus 2 reals for binding), and now to be seen at the Biblioteca Colombina, there is a marginal note attached to these verses: "haec prophetia expleta [=e] per patr[=e] meuz[=z] cristofor[=u] col[=o] almir[=a]t[=e] anno 1492."]
[Footnote 452: [Greek: Kaloumen gar oikoumenen hen oikoumen kai gnorizomen; endeketai de kai en te aute eukrato zone kai dyo oikoumenas einai e kai pleious.] Strabo, i. 4, - 6; [Greek: kai gar ei houtos echei, ouch hypo touton ge oikeitai ton par"
hemin; all" ekeinen allen oikoumenen theteon. hoper esti pithanon. Hemin de ta en aute tauta lekteon.] Id. ii. 5, - 13.
This has always seemed to me one of the most remarkable antic.i.p.ations of modern truth in all ancient literature. Mr.
Bunbury thinks it may have suggested the famous verses of Seneca just quoted. _History of Ancient Geography_, vol. ii. p.
224.]
[Sidenote: Opinions of Christian writers.]
[Sidenote: Roger Bacon.]
[Sidenote: The "Imago Mundi" of Petrus Alliacus.]
Early in the Christian era we are told by an eminent Greek astronomer that the doctrine of the earth"s sphericity was accepted by all competent persons except the Epicureans.[453] Among the Fathers of the Church there was some difference of opinion; while in general they denied the existence of human beings beyond the limits of their Oec.u.mene, or Inhabited World, this denial did not necessarily involve disbelief in the globular figure of the earth.[454] The views of the great ma.s.s of people, and of the more ignorant of the clergy, down to the time of Columbus, were probably well represented in the book of Cosmas Indicopleustes already cited.[455] Nevertheless among the more enlightened clergy the views of the ancient astronomers were never quite forgotten, and in the great revival of intellectual life in the thirteenth century the doctrine of the earth"s sphericity was again brought prominently into the foreground. We find Dante basing upon it the cosmical theory elaborated in his immortal poem.[456] In 1267 Roger Bacon--stimulated, no doubt, by the reports of the ocean east of Cathay--collected pa.s.sages from ancient writers to prove that the distance from Spain to the eastern sh.o.r.es of Asia could not be very great. Bacon"s argument and citations were copied in an extremely curious book, the "Imago Mundi," published in 1410 by the Cardinal Pierre d"Ailly, Bishop of Cambrai, better known by the Latinized form of his name as Petrus Alliacus. This treatise, which throughout the fifteenth century enjoyed a great reputation, was a favourite book with Columbus, and his copy of it, covered with marginal annotations in his own handwriting, is still preserved among the priceless treasures of the Biblioteca Colombina.[457] He found in it strong confirmation of his views, and it is not impossible that the reading of it may have first put such ideas into his head. Such a point, however, can hardly be determined. As I have already observed, these ideas were in the air.
What Columbus did was not to originate them, but to incarnate them in facts and breathe into them the breath of life. It was one thing to suggest, as a theoretical possibility, that Cathay might be reached by sailing westward; and it was quite another thing to prove that the enterprise was feasible with the ships and instruments then at command.
[Footnote 453: [Greek: Hoi de hemeteroi] [i. e. the Stoics]
[Greek: kai apo mathematon pantes, kai hoi pleious ton apo tou Sokratikou didaskaleiou sphairikon einai to schema tes ges diebebaiosanto.] Cleomedes, i. 8; cf. Lucretius, _De Rerum Nat._, i. 1052-1082; Stobaeus, _Eclog._ i. 19; Plutarch, _De facie in Orbe Luna_, cap. vii.]
[Footnote 454: See Augustine, _De civitate Dei_, xvi. 9; Lactantius, _Inst. Div._, iii. 23; Jerome, _Comm. in Ezechiel_, i. 6; Whewell"s _History of the Inductive Sciences_, vol i. p.
196.]
[Footnote 455: See above, p. 266.]
[Footnote 456: For an account of the cosmography of the Divine Comedy, ill.u.s.trated with interesting diagrams, see Artaud de Montor, _Histoire de Dante Alighieri_, Paris, 1841.]
[Footnote 457: It was first printed without indication of place or date, but probably the place was Paris and the date somewhere from 1483 to 1490. Ma.n.u.script copies were very common, and Columbus probably knew the book long before that time. There is a good account of it in Humboldt"s _Examen critique_, tom. i. pp. 61-76, 96-108. Humboldt thinks that such knowledge as Columbus had of the opinions of ancient writers was chiefly if not wholly obtained from Alliacus. It is doubtful if Columbus had any direct acquaintance with the works of Roger Bacon, but he knew the _Liber Cosmographicus_ of Albertus Magnus and the _Speculum Naturale_ of Vincent de Beauvais (both about 1250), and drew encouragement from them.
He also knew the book of Mandeville, first printed in French at Lyons in 1480, and a Latin translation of Marco Polo, published in 1485, a copy of which, with marginal MS. notes, is now in the Colombina.]
[Ill.u.s.tration: Annotations by Columbus.]
[Sidenote: Ancient estimates of the size of the globe and the length of the Oec.u.mene.]
The princ.i.p.al consideration, of course, was the distance to be traversed; and here Columbus was helped by an error which he shared with many geographers of his day. He somewhat underestimated the size of the earth, and at the same time greatly overestimated the length of Asia.
The first astronomer to calculate, by scientific methods, the circ.u.mference of our planet at the equator was Eratosthenes (B. C.
276-196), and he came--all things considered--fairly near the truth; he made it 25,200 geographical miles (of ten stadia), or about one seventh too great. The true figure is 21,600 geographical miles, equivalent to 24,899 English statute miles.[458] Curiously enough, Posidonius, in revising this calculation a century later, reduced the figure to 18,000 miles, or about one seventh too small. The circ.u.mference in the lat.i.tude of Gibraltar he estimated at 14,000 miles; the length of the Oec.u.mene, or Inhabited World, he called 7,000; the distance across the Atlantic from the Spanish strand to the eastern sh.o.r.es of Asia was the other 7,000. The error of Posidonius was partially rectified by Ptolemy, who made the equatorial circ.u.mference 20,400 geographical miles, and the length of a degree 56.6 miles.[459] This estimate, in which the error was less than one sixteenth, prevailed until modern times. Ptolemy also supposed the Inhabited World to extend over about half the circ.u.mference of the temperate zone, but the other half he imagined as consisting largely of bad lands, quagmires, and land-locked seas, instead of a vast and open ocean.[460]
[Footnote 458: See Herschel"s _Outlines of Astronomy_, p. 140.
For an account of the method employed by Eratosthenes, see Delambre, _Histoire de l"astronomie ancienne_, tom. i. pp.
86-91; Lewis, _Astronomy of the Ancients_, p. 198.]
[Footnote 459: See Bunbury"s _History of Ancient Geography_, vol. ii. pp. 95-97, 546-579; Muller and Donaldson, _History of Greek Literature_, vol. iii. p. 268.]
[Footnote 460: Strabo, in arguing against this theory of bad lands, etc., as obstacles to ocean navigation--a theory which seems to be at least as old as Hipparchus--has a pa.s.sage which finely expresses the loneliness of the sea:--[Greek: Hoite gar periplein epicheiresantes, eita anastrepsantes, ouch hypo epeirou tinos antipiptouses kai kolyouses, ton epekeina ploun anakrousthenai phasin, alla hypo aporias kai eremias, ouden hetton tes thalattes echouses ton poron] (lib. i. cap. i. - 8).
When one thinks of this [Greek: aporia] and [Greek: eremia], one fancies oneself far out on the Atlantic, alone in an open boat on a cloudy night, bewildered and hopeless.]
[Sidenote: Toscanelli"s calculation of the size of the earth,]
[Sidenote: and of the position of c.i.p.ango.]
Ptolemy"s opinion as to the length of the Inhabited World was considerably modified in the minds of those writers who toward the end of the Middle Ages had been strongly impressed by the book of Marco Polo. Among these persons was Toscanelli. This excellent astronomer calculated the earth"s equatorial circ.u.mference at almost exactly the true figure; his error was less than 124 English miles in excess. The circ.u.mference in the lat.i.tude of Lisbon he made 26 250 3 = 19,500 miles.[461] Two thirds of this figure, or 13,000 miles, he allowed for the length of the Oec.u.mene, from Lisbon eastward to Quinsay (i. e.
Hang-chow), leaving 6,500 for the westward voyage from Lisbon to Quinsay. Thus Toscanelli elongated Asia by nearly the whole width of the Pacific ocean. His Quinsay would come about 130 W., a few hundred miles west of the mouth of the Columbia river. Zaiton (i. e. Chang-chow), the easternmost city in Toscanelli"s China, would come not far from the tip end of Lower California. Thus the eastern coast of c.i.p.ango, about a thousand miles east from Zaiton, would fall in the Gulf of Mexico somewhere near the ninety-third meridian, and that island, being over a thousand miles in length north and south, would fill up the s.p.a.ce between the parallel of New Orleans and that of the city of Guatemala.
The westward voyage from the Canaries to c.i.p.ango, according to Toscanelli, would be rather more than 3,250 miles, but at a third of the distance out he placed the imaginary island of "Antilia," with which he seems to have supposed Portuguese sailors to be familiar.[462] "So through the unknown parts of the route," said the venerable astronomer, "the stretches of sea to be traversed are not great,"--not much more than 2,000 English miles, not so long as the voyage from Lisbon to the Guinea coast.
[Sidenote: Columbus"s opinion of the size of the globe, the length of the Oec.u.mene, and the width of the Atlantic ocean.]
[Sidenote: The fourth book of Esdras.]
While Columbus attached great importance to these calculations and carried Toscanelli"s map with him upon his first voyage, he improved somewhat upon the estimates of distance, and thus made his case still more hopeful. Columbus was not enough of an astronomer to adopt Toscanelli"s improved measurement of the size of the earth. He accepted Ptolemy"s figure of 20,400 geographical miles for the equatorial girth,[463] which would make the circ.u.mference in the lat.i.tude of the Canaries about 18,000; and Columbus, on the strength of sundry pa.s.sages from ancient authors which he found in Alliacus (cribbed from Roger Bacon), concluded that six sevenths of this circ.u.mference must be occupied by the Oec.u.mene, including c.i.p.ango, so that in order to reach that wonderful island he would only have to sail over one seventh, or not much more than 2,500 miles from the Canaries.[464] An authority upon which he placed great reliance in this connection was the fourth book of Esdras, which although not a canonical part of the Bible was approved by holy men, and which expressly a.s.serted that six parts of the earth (i. e. of the length of the Oec.u.mene, or north temperate zone) are inhabited and only the seventh part covered with water. From the general habit of Columbus"s mind it may be inferred that it was chiefly upon this scriptural authority that he based his confident expectation of finding land soon after accomplishing seven hundred leagues from the Canaries. Was it not as good as written in the Bible that land was to be found there?
[Footnote 461: See above, p. 360. Toscanelli"s mile was nearly equivalent to the English statute mile. See the very important note in Winsor, _Narr. and Crit. Hist._, vol. i. p. 51.]
[Footnote 462: The reader will also notice upon Toscanelli"s map the islands of Brazil and St. Brandan. For an account of all these fabulous islands see Winsor, _Narr. and Crit. Hist._, vol. i. pp. 46-51. The name of "Antilia" survives in the name "Antilles," applied since about 1502 to the West India islands.
All the islands west of Toscanelli"s ninetieth meridian belong in the Pacific. He drew them from his understanding of the descriptions of Marco Polo, Friar Odoric, and other travellers.
These were the islands supposed, rightly, though vaguely, to abound in spices.]
[Footnote 463: Columbus was confirmed in this opinion by the book of the Arabian astronomer Alfragan, written about A. D.
950, a Latin translation of which appeared in 1447. There is a concise summary of it in Delambre, _Histoire de l"astronomie du Moyen age_, pp. 63-73. Columbus proceeded throughout on the a.s.sumption that the length of a degree at the equator is 56.6 geographical miles, instead of the correct figure 60. This would oblige him to reduce all Toscanelli"s figures by about six per cent., to begin with. Upon this point we have the highest authority, that of Columbus himself, in an autograph marginal note in his copy of the _Imago Mundi_, where he expresses himself most explicitly: "Nota quod sepius navigando ex Ulixbona ad Austrum in Guineam, notavi c.u.m diligentia viam, ut solitum naucleris et malineriis, et preteria accepi alt.i.tudinem solis c.u.m quadrante et aliis instrumentis plures vices, et inveni concordare c.u.m Alfragano, videlicet respondere quemlibet gradum milliariis 56-2/3. Quare ad hanc mensuram fidem adhibendam. Tunc igitur possumus dicere quod circuitus Terrae sub arae equinoctiali est 20,400 milliariorum. Similiter que id invenit magister Josephus phisicus et astrologus et alii plures missi specialiter ad hoc per serenissimum regem Portugaliae," etc.; _anglice_, "Observe that in sailing often from Lisbon southward to Guinea, I carefully marked the course, according to the custom of skippers and mariners, and moreover I took the sun"s alt.i.tude several times with a quadrant and other instruments, and in agreement with Alfragan I found that each degree [i. e. of longitude, measured on a great circle]
answers to 56-2/3 miles. So that one may rely upon this measure. We may therefore say that the equatorial circ.u.mference of the earth is 20,400 miles. A similar result was obtained by Master Joseph, the physicist [or, perhaps, physician] and astronomer, and several others sent for this special purpose by the most gracious king of Portugal."--Master Joseph was physician to John II. of Portugal, and was a.s.sociated with Martin Behaim in the invention of an improved astrolabe which greatly facilitated ocean navigation.--The exact agreement with Ptolemy"s figures shows that by a mile Columbus meant a geographical mile, equivalent to ten Greek stadia.]
[Footnote 464: One seventh of 18,000 is 2,571 geographical miles, equivalent to 2,963 English miles. The actual length of Columbus"s first voyage, from last sight of land in the Canaries to first sight of land in the Bahamas, was according to his own dead reckoning about 3,230 geographical miles. See his journal in Navarrete, _Coleccion_, tom. i. pp. 6-20.
I give here in parallel columns the pa.s.sage from Bacon and the one from Alliacus upon which Columbus placed so much reliance.
In the Middle Ages there was a generous tolerance of much that we have since learned to stigmatize as plagiarism.
From Roger Bacon, _Opus From Petrus Alliacus, _De Majus_ (A. D. 1267), London, imagine Mundi_ (A. D. 1410), 1733, ed. Jebb, p. 183:--"Sed Paris, cir. 1490, cap. viii. fol.
Aristoteles vult in fine secundi 13 b:--"Summus Aristoteles Coeli et Mundi quod plus [terrae] dicit quod mare parvum est inter habitetur quam quarta pars. Et finem Hispaniae a parte occidentis Averroes hoc confirmat. Dicit et inter principium Indiae Aristoteles quod mare parvum a parte orientis, et vult quod est inter finem Hispaniae a parte plus habitetur quam quarta occidentis et inter principium pars, et Averroes hoc confirmat.
Indiae a parte orientis. Et Seneca, Insuper Seneca libro libro quinto Naturalium, quinto Naturalium, dicit quod dicit quod mare hoc est navigabile mare est navigabile in paucis in paucissimis diebus si diebus si ventus sit conveniens.
ventus sit conveniens. Et Plinius Et Plinius docet in Naturalibus, docet in Naturalibus quod libro secundo, quod navigatum navigatum est a sinu Arabico est a sinu Arabico usque ad usque ad Gades: unde refert Gades Herculis non multum quendam fugisse a rego suo magno tempore, prae timore et intravit sinum Maris Rubri ... qui circiter spatium navigationis annualis distat a Mari Indico: ... ex quo patet principium Indiae in oriente multum a n.o.bis distare et ab Hispania, postquam tantum distat a principio Arabiae versus Indiam. A fine Hispaniae unde concludunt sub terra tam parvum mare est aliqui, quod mare non est quod non potest cooperire tres tantum quod possit cooperire quartas terrae. Et hoc per tres quartas terrae. Accedit ad auctoritatem alterius considerationis hoc auctoritas Esdrae libro suo probatur. Nam Esdras quarto, dicentis quod s.e.x partes dicit quarto libro, quod s.e.x partes terrae sunt habitatae et terrae sunt habitatae et septima septima est cooperta aquis. Et est cooperta aquis, ne aliquis impediat hanc auctoritatem, dicens quod liber ille est apocryphus et ignotae auctoritatis, dicendum est quod cujus libri auctoritatem sancti sancti habuerunt illum librum habuerunt in reverentia."
in usu et confirmant veritates sacras per illum librum."
Columbus must either have carried the book of Alliacus with him on his voyages, or else have read his favourite pa.s.sages until he knew them by heart, as may be seen from the following pa.s.sage of a letter, written from Hispaniola in 1498 to Ferdinand and Isabella (Navarrete, tom i. p. 261):--"El Aristotel dice que este mundo es pequeno y es el agua muy poca, y que facilmente se puede pasar de Espana a las Indias, y esto confirma el Avenryz [Averroes], y le alega el cardenal Pedro de Aliaco, autorizando este decir y aquel de Seneca, el qual conforma con estos.... a esto trac una autoridad de Esdras del tercero libro suyo, adonde dice que de siete partes del mundo las seis son descubiertas y la una es cubierta de agua, la cual autoridad es aprobada por Santos, los cuales dan autoridad al 3^o e 4^o libro de Esdras, ansi come es S. Agustin e S.
Ambrosio en su _exameron_," etc.--"Singular period," exclaims Humboldt, "when a mixture of testimonies from Aristotle and Averroes, Esdras and Seneca, on the small extent of the ocean compared with the magnitude of continental land, afforded to monarchs guarantees for the safety and expediency of costly enterprises!" _Cosmos_, tr. Sabine, vol. ii. p. 250. The pa.s.sages cited in this note may be found in Humboldt, _Examen critique_, tom. i. pp. 65-69. Another interesting pa.s.sage from _Imago Mundi_, cap. xv., is quoted on p. 78 of the same work.]
[Sidenote: Fortunate mixture of truth and error.]
[Sidenote: The whole point and purport of Columbus"s scheme.]
Thus did Columbus arrive at his decisive conclusion, estimating the distance across the Sea of Darkness to j.a.pan at something less than the figure which actually expresses the distance to the West Indies. Many a hopeful enterprise has been ruined by errors in figuring, but this wrong calculation was certainly a great help to Columbus. When we consider how difficult he found it to obtain men and ships for a voyage supposed to be not more than 2,500 miles in this new and untried direction, we must admit that his chances would have been poor indeed if he had proposed to sail westward on the Sea of Darkness for nearly 12,000 miles, the real distance from the Canaries to j.a.pan. It was a case where the littleness of the knowledge was not a dangerous but a helpful thing.
If instead of the somewhat faulty astronomy of Ptolemy and the very hazy notions prevalent about "the Indies," the correct astronomy of Toscanelli had prevailed and had been joined to an accurate knowledge of eastern Asia, Columbus would surely never have conceived his great scheme, and the discovery of America would probably have waited to be made by accident.[465] The whole point of his scheme lay in its promise of a shorter route to the Indies than that which the Portuguese were seeking by way of Guinea. Unless it was probable that it could furnish such a shorter route, there was no reason for such an extraordinary enterprise.
[Footnote 465: See below, vol. ii. p. 96.]
[Sidenote: Columbus"s speculations on climate.]
[Sidenote: His voyage to Guinea.]