SCIENCE OF THE ROMAN PERIOD 



earth. This matter, Strabo thinks, "should have been 

 disposed of in the compass of a few words. ' ' Obviously 

 this doctrine of the globe's sphericity had, in the course 

 of 600 years, become so firmly established among the 

 Greek thinkers as to seem almost axiomatic. We 

 shall see later on how the Western world made a curi- 

 ous recession from this seemingly secure position under 

 stimulus of an Oriental misconception. As to the size 

 of the globe, Strabo is disposed to accept without par- 

 ticular comment the measurements of Eratosthenes. 

 He speaks, however, of "more recent measurements," 

 referring in particular to that adopted by Posidonius, 

 according to which the circumference is only about 

 one hundred and eighty thousand stadia. Posidonius, 

 we may note in passing, was a contemporary and 

 friend of Cicero, and hence lived shortly before the 

 time of Strabo. His measurement of the earth was 

 based on observations of a star which barely rose above 

 the southern horizon at Rhodes as compared with the 

 height of the same star when observed at Alexandria. 

 This measurement of Posidonius, together with the 

 even more famous measurement of Eratosthenes, ap- 

 pears to have been practically the sole guide as to the 

 size of the earth throughout the later periods of an- 

 tiquity, and, indeed, until the later Middle Ages. 



As becomes a writer who is primarily geographer and 

 historian rather than astronomer, Strabo shows a 

 much keener interest in the habitable portions of the 

 globe than in the globe as a whole. He assures us that 

 this habitable portion of the earth is a great island, 

 " since wherever men have approached the termination 

 of the land, the sea, which we designate ocean, has 



259 



