An Account of the Latitude of Constantinople, and Rhodes, Written by the Learned Mr John Greaves, Sometime Professor of Astronomy in the University of Oxford, and Directed to the Most Reverend James Ussher, Arch-Bishop of Armagh

the Danish and Saxon tongues: but that can be no other than the natural effect of the two Nations being jumbled together in this part of the World. Our Borderers, to this day, speak a Leash of Languages (Brittish, Saxon, and Danish) in one; and 'tis hard to determine, which of those three nations has the greatest share in the Mottly Breed. Sr, Your, &c. W. N. An account of the Latitude of Constantinople, and Rhodes, Written by the Learned Mr John Greaves, sometime Professor of Astronomy in the University of Oxford, and directed to the most Reverend James Usher, Arch-Bishop of Armagh. Upon Intimation of your Grace's desires, and upon opportunity of some Learned Men, having finished a Table, as a key to your Grace's exquisite disquisition, touching Asia properly so called; I thought myself 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 bounds of the Chart,) I dissent from the traditions of the Antients, 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 City's 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 μεγαλης or Almagest, as the Arabians term it, where describing the Parallel passing Ἀλβιζάνης, he assigns to it 43° 5'. What was the opinion concerning Byzantium of Strabo preceding Ptolemy, or of Hipparchus preceding Strabo, or of Eratothenes ancienier, and it may be accurater then all of them, (for Strabo, (Lib. 2.) calls him πλευρῶν περιγραφομένου ὡς ἐν τῇ Ἑλλάδι) though Tully (Lib. Ep. ad Att.) makes Hipparchus often reprehended Eratothenes, 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 inquiry, 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 judgement,) then 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 lasy for these reasons we can expect little satisfaction from Strabo, and less may we hope for from Dionysius Afer, Arrianus, Stephanus Byzantinus, & others. Wherefore next having recourse to the Arabians, who in Geography deserve the second place after the Graecians, I find in Nassir Eddin the Latitude of Byzantium, which he terms Buzantiya, and Constantiniya, to be 45 degrees, and in Ulug Begs Astronomicall Tables the same to be expressed. Abulfeda chiefly follows four Principall Authors as his Guides, in the compiling of his Geographical Tables, those are, Alfaras, Albiruny, Hon Saïid 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 wondered, 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 expressly relates, that Ptolemy was first interpreted in his time, that is, in the computation of Almecinus 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 περίχωρα ναυάρις 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 Authors, will not help us in this particular; seeing the Greek Copies agree gree amongst themselves, and the Arabick Copies amongst themselves. The best way to end the dispute, will be, to give credit concerning the Latitude or 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 4 foot Radius. Where taking, in the Summer Solstice, the Meridian Altitude of the Sun, without using any προσφυγεῖς, 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 Corollary, That all Maps for the North East of Europe, and of Asia, adjoining 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 Λονδίνων, that is London, in 54 degrees of Latitude; and the ἡμέρα or the middle of the Isle of Wight, (which in the printed Copies is falsely termed ἀκτήνης, but in the MSS. rightly ἀκτήνης,) in 52 degrees and 20 minutes of Latitude. tude. 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 judgement 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 Travailers, 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 joined 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 travelers, 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 σωματος) of 920 furlongs circuit, where according to Ptolemy the Parallel passing δια ρος, hath 36 degrees of Latitude, and so hath Lindus, and ἐνδυνατος the chief Cities of the Island; the same is confirmed by the MS. but where the printed Copy, and Eustathius read ἐνδυνατος, which Mercator renders Talyssus, the MS renders ἐνδυνατος. 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 $37^\circ$ and $50'$. A larger Instrument I durst not adventure to carry on shore in a place of so much jealousy. 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, then with Ptolemy, whom I know not how to excuse. Francisci