752 GEOGRAPHICAL LATITUDE. 



exactly corresponding to the five circles of the heaven. ^ Pliny, on the 

 other hand, takes the names of the zones literally, and considers the 

 whole torrid zone uninhabitable, and so preventing all intercourse 

 between the two temperate zones.^ 



The Greeks however did not arrive at one bound at the exact divis- 

 ion of the earth's surface. The starred heavens passed over their heads, 

 making it impossible to see and study much while remaining at the 

 same place. Exact knowledge of the world was not thus attainable; 

 practical information gained by observation and travel was necessary 

 as a foundation for the complete application to geography of the lines of 

 astronomy. Though adopting theoretically the five main parallels of 

 the astronomers, the early geographers felt the necessity of having a 

 working basis ; and, leaving the equator at one side as a practically un- 

 known quantity, they adopted as a central line, a parallel passing 

 through a place, (Rhodes,^) not only important in itself, but also for 

 them, the practical middle between the north and south, inhabited world. 

 This line was proposed by Eratosthenes, and passed from the Pillars of 

 Hercules through the Strait of Messina, Southern Greece, Rhodes, then 

 on through Asia to the mountains forming the (imaginary) northeast 

 boundary of India.^ This parallel is known as the Diaphragm, and 

 is generally supposed to have been so named by the Greeks,^ but a 

 modern French investigator says he was unable to find this designation 

 among the ancient Greek geographers.*^ Following the policy of em- 

 ploying an arbitrary line as a center, largely if not mainly because of 

 its local importance, other parallels to the north and south were adopted 

 because they passed through well known places. The spaces thus 

 divided off, had no fixed arithmetical relation, but were supposed to mark 

 climatical differences, and received hence the name climates. Eratos- 

 thenes made a division of the entire known earth into four great rect- 

 angles which he called Sphragides,'^ and these in turn into twelve cli- 

 mates.^ The latter were reduced to eight by Hipparchus,^ and later 

 increased '"^ until they became, in the work of Ptolemy, twenty-three." 

 However, the division of the earth into five zones, as is now cus- 

 tomary, was adopted by Parmenides, sanctioned by the authority of 



'Grosskurd's Strabo, lib. ii. Abt. iv. § 3. Vol. i, pp. 181-2. 



-Scrack's Plinius, i. iii. lib. ii. 68. 



^Berger, Frag. d. Hipparcb, 72. Grossknrd's Strabo, lib. ii. Abt. i. vS 1. note 1. p. 

 110. Used first by Diciearcbos. Maanert i. 90. 



■•Forbiger's Strabo, lib. ii. cap. i. § 1. Manuert, i. 90, gives tbe bouor of lirst baving 

 proposed this line to DictBarcbus. 



°Terin already employed by Dictearcbus, Sprenger, Ausland, 1867, p. 1045. Gross- 

 kurd's Strabo, lib. ii. Abt. i. § 1, uote 1, p. 110. 



^D'Avezac, Coup d'ccil, etc., p. 269, note 9. 



'Grossknrd's Strabo, lib. i. Abt. i. § 13. Vol. i. p. 128. 



«Lelewel, Bres. Ed. i. x. 



9 Grossknrd's Strabo, i. 215-17, lib. ii. Abt. iv. ^ 26, 



'I' Sprenger, Ausland, 1867, p. 1043. 



" Manuert, i. 130, 



