NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Wolfgang Köberer
Date: 2009 Nov 4, 21:46 +0100
Now that all the pleasantries have
been exchanged, I may return to the original questions in this
thread:
John Huth
asked:
"1.) What evidence is there for Portuguese
vessels sailing on a far west path around West Africa - getting close to what is
now Brazil?
2.) Any idea what modern town
Sigdemessah might be?
Timbuktu?"
Ad 1: The passage back from Guinea
(and later from India/the Moluccas) „on a far west path around West Africa” had
been established by the Portuguese in the second half of the 15. century. It was
called the “Volta da Mina” (from Guinea) or the “Volta do mar largo” (from
farther down south). It was necessitated, indeed, by the trades: the Portuguese sailors could not hug the African
coast going north so turned norhwest and later east. This practise was
facilitated by the development of the “Caravel” with lateen rig.
This practice was - by the way -
also the incentive to develop celestial navigation, as traditional methods of
navigation obviously could not be of
any help out on the ocean. This method and the development of celestial
navigation has been studied in depth by Portuguese historians of navigation
since the beginning of the last century; among others Bensaude, Coutinho,
Cortesao, Albuquerque etc. A basic text - in English - is in Vol. II of
Cortesao’s “History of Portuguese Cartography” (Coimbra 1971). This text
(“Astronomical navigation” and “Instruments of Navigation”) by Luis de
Albuquerque has also been published separately. And there are still Portuguese
scholars publishing relevant contributions today, among them Estacio Dos Reis
and Captain Malhao Pereira whom some list members have met a couple of years ago
at the Instrument Symposium at Greenwich.
Ad 2: This is a very difficult
question: What you are trying to do is to identify an ancient name with a modern
location and then assess the accuracy of the ancient positional data. There are
several problems - all very well explored in the study of portolan charts - the
most difficult being the identification of the ancient place. This has been
illustrated quite well by Peter and George trying to create plausibilities by arguments from a completely different
field: French history. Now I am not versed in French history and its intricacies
at all; I just noted that the latitudes in the tables you gave do not fit the
place they discussedl. They agree roughly with Lyon (and not with Laon). That
makes me wonder because - of course - latitudes could be measured very
easily even at that time and should
not be out by many degrees. As far as longitudes are concerned they depend, of
course, on the meridian of zero longitude that the author of the tables choses -
and that might be another difficulty.
So trying to fit the positional data of ancient
tables with modern data is interesting - I’ve tried it myself in analysing the
tables of the oldest German manual of navigation - but sometimes you are left
just guessing.
Regards
--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList+@fer3.com
-~----------~----~----~----~------~----~------~--~---