<<The idea that Columbus was opposed by people who maintained that
the earth was about 25,000 miles in diameter occurs frequently in the
secondary literature, but I have never seen any serious evidence for
it. It seems to be merely people's idea of what should have happened.
The relevant accounts in the biography by Columbus's son Ferdinand
and in Las Casas agree that the opponents arguing about the size of
the earth said either
(1) that the world was infinitely large and so it was impossible to
reach Asia ("que el mundo era de infinita grandeza, y por tanto no
seri'a posible en muchos an~os navegando se pudiese llegar al fin de
Oriente") -- Las Casas, Chapter 29; or
(2) that to reach the edge of Asia would take more than three years,
... [and] many learned men were in disagreement on the question whether
the ocean was infinite (Life of Columbus, Chapter 14).>>
These sources are certainly closer to the time than mine, which was Morison's
biography of Columbus, but both writers might conceivably have had an
interest in exaggerating the academics' objections. (Could those tonsured
profs. really envisage an "infinite" ocean? The infinitude of the entire
universe was a suspect notion up to 1600.) Though I do not have Morison's
bio. handy at the moment, I seem to remember that Morison consulted the
records of the Salamanca disputation itself in order to claim that the
professors knew their Eratosthenes and Ptolemy better than Columbus did,
and if that is the case, Morison's evidence would count as "serious." The
reference to Columbus's reliance on Pierre D'Ailly is found both in Morison
and in histories of science I have hitherto relied on. I note that old
Christ-Bearing Dove was still getting his longitudes bunched up when he
famously predicted that eclipse. (And BTW I hope that all of you on the
ecliptic enjoyed the show.)
Let me correct myself further in September when I can consult the books.
And end by quoting the nice caveat that just came in from Juan Jose Castillos:
<<For instance, it's usually difficult for Mathematicians to grasp the basic
historical fact that if one of their conclusions implies a greater degree of
sophistication in the people they deal with than is warranted by the body of
other evidence we have on that culture, then the conclusion is suspect
because it exceeds that people's capability. It's more reasonable to conclude
that the new alleged evidence is the result of a misinterpretation than to
change our whole perception (based on millions of independent pieces of
evidence gathered over the years) of the people involved and their culture,
based on that single new element.>>
Bill Everdell, Brooklyn