[658] _Conv._ II. vii. 104-108. ------------------------------------------------------------------------ Mercury is spoken of in the _Paradiso_ as a small star, “Questa picciola stella,”[659] and in _Conv._ II.[660] Dante says:—“Mercury is the smallest star in the sky; for the length of its diameter is not more than 232 miles, according to Alfraganus, who says that it is one twenty-eighth of the diameter of the earth,[661] which is six thousand five hundred miles.” ------------------------------------------------------------------------ [659] “This small star.” _Par._ vi. 112. [660] _Conv._ II. xiv. 92-98. [661] The Frankfort printed edition and some Latin MSS of Alfraganus agree with this: the edition of Golius gives ¹/₁₈. ------------------------------------------------------------------------ It is only in the last passage that our poet quotes his authority, but in the others also the diameter or the semi-diameter of the earth is used as the unit of measure, and it is the same as that given by Alfraganus; so are the sizes of Mercury and the Sun, and the least distance of Venus is the value given by Alfraganus for the greatest distance of Mercury, which he asserted to be equal. It seems quite clear, therefore, that the figures given in the tables on pp. 189-90 represent Dante’s belief as to the dimensions of the Universe. These passages also are another proof that Dante had not studied Ptolemy’s own work, for Ptolemy had said that the distances of Venus and Mercury could not be accurately known.[662] ------------------------------------------------------------------------ [662] _Almagest_, Bk. IX. ------------------------------------------------------------------------ We do not expect exact measures of distance in Dante’s descriptions of his soaring flight through the spheres, but he so constantly speaks of the marvellous speed with which he passes from star to star that we are not required to ignore the stupendous distances between. The one indication he does give us of the space which separates him from earth is full of poetry and symbolic meaning: I refer to Folco’s words in the heaven of Venus:— “Questo cielo, in cui l’ombra s’appunta Che il vostro mondo face” ...[663] ------------------------------------------------------------------------ [663] “This heaven, where ends the shadowy cone Cast by your world.” _Par._ ix. 118, 119. (_Longfellow_). ------------------------------------------------------------------------