340 PTOLEMY AND LATER GEOGRAPHERS. [CHAP.
it was imperfect we gather from Ptolemy, who, while he extols
the diligence of Marinus in collecting and sifting
Deficiencies. ^is data, and notes that in the successive editions
of his work he had done his best to amend and
supplement it, remarks also that much was left for himself to
accomplish in correcting and improving it, To this must be
added a more serious deficiency arising from want of method, for
the continuity of the treatise was much broken up by the insertion
of discussions of disputed points. The map also left much to be
desired, because the parallels of latitude and meridians of longi-
tude were represented upon it throughout by straight lines, and
the meridians of longitude were drawn parallel to one another—
a system, of the faultiness of which Marinus shewed himself to be
aware in the criticisms which he passed on the attempts of his
predecessors to delineate the spherical surface of the globe on a
plane map1.
Of the life of Claudius Ptolemy hardly anything is known, but
it is probable that he studied and wrote at Alex-
Ptolemy.
andria, where the renowned school of letters which
had been founded by the Greek rulers of Egypt still flourished.
His treatise on geography was published subsequently to the
completion of his astronomical works, and its date may be fixed
approximately at 150 A.D. The greatness of his
Reputation! fanie as a mathematical geographer, which is
superior to that enjoyed by any other ancient
writer on the subject, has arisen from several causes. In the first
place it is to be attributed to the age in which he lived, for it
coincided with the decline of learning among the Greeks and
Romans, and in consequence of this he towered so conspicuously
above the writers who followed him, that an undue importance
was attached to his statements. No doubt, also, the renown of
Ptolemy as an astronomer was reflected on his geographical
studies, and heightened the estimation in which they were held.
1 Ptol. i. so. 3, 4; Sirep Ma/wos els MffTww o& rty rvxodffw &ya,y&pt xai
irdrus dTaŁa*rXws /le/t^AjLtevos ra?s fLe668ois r&y tiriirtdw Ka,Ttiypa,<J>uv, ottep
yrrov aMs 0aberai Kexjnj^os rj jadXtora M irotofofl ffvw&povs TAs &a<rreŁ-
<ras' ,rets /i& ykp forl T&V K&K\W ypaptdn r&v
edfclas dTCor^raro vdtras.