782 GEOGRAPHICAL LATITUDE. 



actual survey, bat relied blindly on the map of the world.^ Between 

 these two extremes are found those who prefer to take the results as 

 they are repocted to us, and interpreting them in accordance with what 

 is known as to the then condition of science, come probably nearer the 

 truth. Thus attention is called to the sources of error in the work : 

 that the length of the arc between the end points, Alexandria and 

 Syene, was accepted as much greater than it is, Syene lying north of 

 the Ecliptic; that these places are not on the same meridian,^ and, fur- 

 thermore, that no account was taken of the apparent radius of the sun. 

 With these important sources of error at hand it may well be accepted 

 in accordance with the opinion of Lepsius,^ Giiuther,* and Ideler^ that 

 the error amounted to about 14 per cent., for which however consid- 

 ering all the circumstances, we are not justified in complaining of the 

 work. 



Though this was the nearest approach to the truth made in ancient 

 times, there were other figures accepted by various classical writers, 

 and one which later received more general acceptance among the an- 

 cients and exercised more influence in modern times. This is that which 

 gives to the earth the circumference of 180,000 stadii, generally attrib- 

 uted to Poseidonius, and probably verified by Simplicias. The former 

 enters into considerable detail also as to how he arrived at another re- 

 sult, 240,000 stadii,^ and then he rejects it without explanation in favor 

 of the much smaller and less accurate estimate, namely 180,000 stadii. 

 Simplicius, on the other hand, describes minutely the manner of arriv- 

 ing at this result. The astronomers sought out, he says, two stars ex- 

 actly one degree apart, found the places where these stars passed 

 through the respective zeniths, and by " operations " measured the ter- 

 restrial distance, finding it to be 500 stadii.'^ Delambre is positive that 

 this was only imagined and never carried out.^ But why not ? Ac- 

 cording to a calculation of Alexander von Humboldt, this is as nearly 

 accurate within 7,000 toises (though on the other side), as the measure- 

 ment of Eratosthenes.^ When one considers the great crudity of the 

 means then at command, it is a perfectly possible result of an actual 

 measurement. If it rested on no good foundation, how came it that 

 the great authority of Eratosthenes and Hipparchus, still followed in 

 other respects, was rejected by Ptolemy and his successors as to this ? 



lAusland, 1867, p. 1066. 



^Grosskurd's Strabo, lib. i. Abt. iv, p. 99, An. 2. 



'In Zeitsch. fiir aegypt. Sprach und Alterthunis-Kunde, xv. p. 7. 



■• In Rundschau fiir Geog. nnd Statistik, III. Jahrg. p. 335, where he gives a masterly 

 r6sum6 of the subject. 



eZach, Mon. Cor., May, 1811, p. 474. 



^Sprenger, Ausland, 1867, p. 1067. This is the value accepted in Babylon three 

 hundred years before Christ. Ibid., 1068. 



Udeler, in Zach's Mon. Cor., May, 1811, p. 478,479. 



*Astron. aucienne, I, 304. 



9 Humboldt, G€og. du xv"* sifecle, ii, 326, 327. 



