Re: Ken Towe on VM (Re: Vinland map and Historia Tartarorum, question

Apparently on date Mon, 12 Sep 2005 20:34:45 -0500, kenney@xxxxxxxxxxxxxxxxxxx
said:

>In article <80tai156seifco6g02rfg7ob4le0voud5q@xxxxxxx>,
>nospam@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx () wrote:
>
>> How would this affect his timing of the eclipses?
>
> Does not effect timing, but it could mean he was measuring at a point
>that was 3000, or 5000 miles from his base point so altering the
>maths. The use of time difference to measure a position by longitude
>needs a correct definition of a degree of longitude. IIRC correctly
>that was first established on land, where triangulation could be used
>to measure the distance between two points.

I was under the impression that using hours for longitude goes back at least to
Ptolemy, and in fact at Salamanca, Columbus was disputing the 12 hours of
Ptolemy for Eurasia and instead, arguing for the 15 hours for the same
longitude, as given by the pheonician Marinus of Tyre, thus shortening the
Great Ocean from 12 to 9 hours of longitude, at a stroke.

I mean, these times are actually longitudes. When Columbus gave a figure of 5
and half hours, difference from Saona Island to Cape sao Vincente, he is giving
a longitude of 5.5 hours out of the 24 in a great circle. He is entirely aware
of this.

The distance from SI to CsV affects how large the earth is, not the longitudes.
Columbus was arguing for a smaller earth and gave erroneous longitudes to
suggest the earth was actually smaller, or so this theory says. I'm not 100%
married to the theory, by the way, but it's got more than enough truth in it to
rule out the possibility of Columbus actually wanting to find America rather
than China.


.

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