A Collection of Curious Travels and Voyages, Volume 2 · Body of volume 2 · Section 4
An Account of the Latitude of Conſtantinople and Rhodes; written by the Learned Mr. John Greaves, ſometime Profeſſor of Aſtronomy in the Ʋniverſity of Oxford, and directed to the moſt Reverend James Usſher, Archbiſhop of Ardmagh.
UPON intimation of your Grace's Deſires, and upon importunity of ſome Learned men, having finiſhed a Table, as a Key to your Grace's exquiſite diſquiſition, touching Aſia, properly ſo called; I thought my ſelf obliged to give both you and them a reaſon, why in the ſituation of Byzantium, and the Iſland Rhodus, (which two eminent places I have made the foreign and Bounds of the Chart) I diſſent from the Traditions of the Ancients, and from the Tables of our late and beſt Geographers, and conſequently diſſenting in theſe, have been neceſſitated to alter the Latitudes, if not Longitudes, of moſt of the remarkable Cities of this Diſcourſe. And firſt for Byzantium, the received Latitude of it by Appianus, Mercator, Ortelius, Maginnus, and ſome others, is 43 degrees and 5 minutes. And this alſo we find in the Baſil Edition of Ptolemy's Geography, procured by Eraſmus out of a Greek MS. of Pettichius. The ſame likewiſe is confirmed by another choice MS. in Greek, of the moſt learned and judicious Mr. Selden, to whom for this favour and ſeveral others I ſtand obliged. And as much is expreſſed in the late Edition of Ptolemy by Bertius, compared and corrected by Sylburgius, with a Manuſcript out of the Palatine Library. Wherefore it cannot be doubted, having ſuch a cloud of Witneſſes, but that Ptolemy aſſigned to Byzantium, as our beſt modern Geographers have done, the Latitude of 43°. 5′. And this will farther appear, not only out of his Geography, where it is often expreſſed, but alſo out of his foreign or Almageſt, as the Arabians term it, where deſcribing the Parallel paſſing foreign, he aſſigns to it 43°. 5′. What was the Opinion concerning Byzantium of Strabo preceding Ptolemy, or of Hipparchus preceding Strabo, or of Eratoſthenes ancienter, and it may be accurater than all of them, (for Strabo (lib. 2.) calls him foreign) though Tully (Lib. Ep. ad Att.) makes Hipparchus often reprehended Eratoſthenes, as Ptolemy after him doth Marinus, their Writings not being now extant, (unleſs thoſe of Strabo) cannot be determined by us. But as for Strabo, in our enquiry, we can expect little ſatisfaction; for his deſcription of places, having more of the Hiſtorian and Philoſopher, (both which he hath performed with ſingular Gravity and Judgment) than the exactneſs of a Mathematician, who ſtrictly reſpects the Poſition of places, without inquiſition after their Nature, Qualities, and Inhabitants, (though the beſt Geography would be a mixture of them all, as Abulfeda, an Arabian Prince in his Rectification of Countries above Three hundred years ſince hath done;) I ſay for theſe Reaſons we can expect little ſatisfaction from Strabo, and leſs may we hope for from Dionyſius Afer, Arrianus, Stephanus Byzantinus, and others. Wherefore next having recourſe to the Arabians, who in Geography deſerve the ſecond place after the Grecians, I find in Naſſir Eddin the Latitude of Byzantium, which he terms Buzantiya, and Conſtantiniya, to be 45 degrees, and in Ulug Beg's Aſtronomical Tables the ſame to be expreſſed. Abulfeda chiefly follows four principal Authors as his Guides, in the compiling of his Geographical Tables, thoſe are Alfaras, Albiruny, Hon Saiid Almagraby, laſtly, Ptolemy, whoſe Geography he terms a deſcription of the Quadrant, (or the fourth part of the Earth) inhabited; and all theſe, according to his aſſertion, place Byzantium in 45 degrees of Latitude. And here it may juſtly be wonder'd how this difference ſhould ariſe between the Greek Copies of Ptolemy, and thoſe tranſlated into Arabick by the command of Almamon, the learned Calife of Babylon; for Abulfeda expreſly relates, that Ptolemy was firſt interpreted in his time, that is, in the computation of Almeeinus, in Erpenius's Edition, and of Emir Cond a Perſian Hiſtoriographer, more than 800 years ſince; concerning which Abulfeda writes thus, This Book (diſcourſing of Ptolemy's Geography) was tranſlated out of the Graecian Language into the Arabick for Almamon: And in this I find (by three fair MSS of Abulfeda) Byzantium to be conſtantly placed in 45°. and as conſtantly in the Greek Copies in 43°. 5′. But in the foreign of Chryſococca, out of the Perſian Tables, (made about the year 1346. in Scaliger's Calculation) it is placed in 45°. To reconcile the difference between the Greeks and Arabians, may ſeem impoſſible, for the common refuge of flying to the corruption of numbers by Tranſcribers, and laying the fault on them, which ſometimes is the Author's, will not help us in this particular; ſeeing the Greek Copies agree amongſt themſelves, and the Arabick amongſt themſelves. The beſt way to end the Diſpute, will be, to give credit concerning the Latitude of Byzantium, neither to the Greeks nor Arabians. And that I have reaſon for this Aſſertion, appears by ſeveral Obſervations of mine at Conſtantinople, with a Braſs Sextant of above four foot Radius. Where taking, in the Summer Solſtice, the Meridian Altitude of the Sun, without uſing any foreign for the Parallax and Refraction, (which at that time was not neceſſary) I found the Latitude to be 41 degrees 6 minutes. And in this Latitude in the Chart I have placed Byzantium, and not in that either of the Greeks or Arabians. From which Obſervation, being of ſingular uſe in the rectification of Geography, it will follow by way of Corallary, that all Maps for the North-Eaſt of Europe, and of Aſia, adjoyning upon the Boſphorus Thracius, the Pontus Euxinus, and much farther, are to be corrected; and conſequently the ſituation of moſt Cities in Aſia properly ſo called, are to be brought more Southerly than thoſe of Ptolemy, by almoſt two entire degrees, and then thoſe of the Arabians, by almoſt four.
Concerning Rhodes, it may be preſumed, that having been the Mother, and Nurſe of ſo many eminent Mathematicians, and having long flouriſhed in Navigation, by the direction of theſe, and by the vicinity of the Phoenicians, they could not be ignorant of the preciſe Latitude of their Country, and that from them Ptolemy might receive a true information. Though it cannot be denied, but that Ptolemy, in places remoter from Alexandria, hath much erred. I ſhall only inſtance in our own Country, where he ſituates foreign, that is London, in 54 degrees of Latitude, and the foreign, or the middle of the Iſle of Wight, (which in the printed Copies is falſly termed foreign, but in the MSS rightly foreign) in 52 degrees, and 20 minutes of Latitude. Whereas London is certainly known to have for the Altitude of the Pole, or Latitude of the place, only 51 degrees and 32 minutes; and the middle of the Iſle of Wight not to exceed 50 degrees, and ſome minutes.
But in my judgment Ptolemy is very excuſable in theſe and the like Errors, of ſeveral other places far diſtant from Alexandria, ſeeing he muſt for their poſition neceſſarily have depended either upon relations of Travellers, or Obſervations of Mariners, or upon the Longitude of the day, meaſured in thoſe times by Clepſydrae; all which how uncertain they are, and ſubject unto Error, if ſome celeſtial Obſervations be not joyned with them, and thoſe exactly taken with large Inſtruments, (in which kind the Ancients have not many, and our times, (excepting Tycho Brahe, and ſome of the Arabians) but a few) I ſay no man, that hath converſed with modern Travellers and Navigators, can be ignorant. Wherefore to excuſe theſe Errors of his (or rather of others fathered by him) with a greater abſurdity, by aſſerting the Poles of the World ſince his time to have changed their ſite, and conſequently all Countries their Latitudes, as Mariana the Maſter of Copernicus, and others after him have imagined; or elſe to charge Ptolemy, being ſo excellent an Artiſt, with Ignorance, and that even of his own Country, as Cluverius hath done, (from which my Obſervations at Alexandria and Memphis may vindicate him) the former were too great a ſtupidity, and the latter too great a Preſumption. But to return to Rhodes, an Iſland (in Euſtathius's Comment upon Dionyſius's foreign) of 920 furlongs circuit, where according to Ptolemy, the Parallel paſſing foreign, hath 36 degrees of Latitude, and ſo hath Lindus, and foreign the chief Cities of the Iſland; the ſame is confirmed by the MS, but where the printed Copy and Euſtathius read foreign, which Mercator renders Talyſſus, the MS renders foreign. Abulfeda in ſome Copies ſituates the Iſland Rhodes, (for he mentions no Cities there) in the Latitude of 37 degrees and 40 minutes: And the Geography of Said Ibn Aly Algiorgany, commended by Gilbertus Gaulmyn, in 37 degrees, if it be not by a tranſpoſition in the MS of the numerical Letters in Arabic, 37 for 36. which by reaſon of their ſimilitude, are often confounded in Arabick MSS. By my Obſervations under the Walls of the City Rhodes, with a fair Braſs Aſtrolabe of Gemma Friſius, containing 14 inches in the diameter, I found the Latitude to be 37° and 50′. A larger Inſtrument I durſt not adventure to carry on ſhore in a place of ſo much jealouſie. And this Latitude in the Chart I have aſſigned to the City Rhodes, (from the Iſland ſo denominated, upon which on the North-eaſt ſide it ſtands ſituated) better agreeing with the Arabians than with Ptolemy, whom I know not how to excuſe.