island he would only have to sail over one seventh, or
not much more than 2,500 miles from the Canaries.[464] An authority upon
which he placed great reliance in this connection was the fourth book
of Esdras, which although not a canonical part of the Bible was approved
by holy men, and which expressly asserted that six parts of the earth
(i. e. of the length of the Oecumene, or north temperate zone) are
inhabited and only the seventh part covered with water. From the general
habit of Columbus's mind it may be inferred that it was chiefly upon
this scriptural authority that he based his confident expectation of
finding land soon after accomplishing seven hundred leagues from the
Canaries. Was it not as good as written in the Bible that land was to be
found there?

[Footnote 461: See above, p. 360. Toscanelli's mile was nearly
equivalent to the English statute mile. See the very important
note in Winsor, _Narr. and Crit. Hist._, vol. i. p. 51.]

[Footnote 462: The reader will also notice upon Toscanelli's
map the islands of Brazil and St. Brandan. For an account of
all these fabulous islands see Winsor, _Narr. and Crit. Hist._,
vol. i. pp. 46-51. The name of "Antilia" survives in the name
"Antilles," applied since about 1502 to the West India islands.
All the islands west of Toscanelli's ninetieth meridian belong
in the Pacific. He drew them from his understanding of the
descriptions of Marco Polo, Friar Odoric, and other travellers.
These were the islands supposed, rightly, though vaguely, to
abound in spices.]

[Footnote 463: Columbus was confirmed in this opinion by the
book of the Arabian astronomer Alfragan, written about A. D.
950, a Latin translation of which appeared in 1447. There is a
concise summary of it in Delambre, _Histoire de l'astronomie du
Moyen Age_, pp. 63-73. Columbus proceeded throughout on the
assumption that the length of a degree at the equator is 56.6
geographical miles, instead of the correct figure 60. This
would oblige him to reduce all Toscanelli's figures by about
six per cent., to begin with. Upon this point we have the
highest authority, that of Columbus himself, in an autograph
marginal note in his copy of the _Imago Mundi_, where he
expresses himself most explicit