=A.= THE FORM OF THE EARTH.—It is not easy to demonstrate that the earliest Greeks believed the earth to be a flat disk, although that is the accepted and probably correct view of their belief. It is possible to examine but a small part of the earliest literature, and what we have is of uncertain date and dubious origin; its intent is religious or romantic, not scientific; its form is poetic. It is difficult to interpret it accurately, since the prevalent ideas of nature must be deduced from imagery, qualifying words and phrases, and seldom from direct description. The interpreter, doubtful as to the proportion in which he finds mingled fancy and honest faith, is in constant danger of overreaching himself by excess of ingenuity. In dealing with such a literature one is peculiarly liable to abuse the always dangerous argument by which want of knowledge is inferred from lack of mention. Other difficulties beset the use of later philosophic material, much of which is preserved only in extracts made by antagonists or by compilers, so that we are forced to confront a lack of context and possible misunderstanding or misquotation. The frequent use of the word _στρογγύλος_, which has the same ambiguity as our word “round” in common parlance, often leads to uncertainty. A more fruitful cause of trouble is inherent in the Greek manner of thinking of the world. It is often difficult to know whether a writer means the planet, or whether he means the agglomeration of known lands which later writers called _ἡ οἰκουμένη_. It is not impossible that when writers refer to the earth as encircled by the river Oceanus, they mean, not the globe, but the known lands, the eastern continent, as we say, what the Romans sometimes called _orbis terrae or orbis terrarum_, a term which may mean the “circle of the lands,” not the “orb of the earth.” At a later time it was a well-known belief that the earth-globe and water-globe were excentrics, so that a segment of the former projected beyond the surface of the latter in one part, and constituted the known world.[358]