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I don't think it is just that. If you haven't read Ptolomy (and in particular all of Tetrabiblos, the Almagest, and his Geographia), you really should. Ptolom

I don't think it is just that. If you haven't read Ptolomy (and in particular all of Tetrabiblos, the Almagest, and his Geographia), you really should. Ptolomy was quite an incredibly observant individual and he worked through things with an attention to detail that is quite impressive. He clearly understood he was in the Northern Hemisphere, but he placed Alexandria not in the southernmost part of the known world as the article suggests but in the center. A lot of this was pride and the sense that the center had everything good from the edges (see Tetrabiblos), but to some extent everywhere is the center, right? He painstakingly discusses the proof that the earth is a sphere in Almagest. His geographia is worth reading and directly relevant to this. I suspect that Ptolomy put the north at the top simply because he was in the Northern Hemisphere and knew it. He displays no great knowledge of navigation, though he does explain how the stars shift as you move north and south (again see Tetrabiblos and Almagest), and he even seemed to be aware that Mercury and Venus revolved around the sun (or so he seemed to say in Tetrabiblos). All in all he's one of those authors one really has to read if one is interested in history, even the seemingly weird works he wrote (Tetrabiblos is an astrology manual but includes a lot of information about Ptolomy's understanding of geography not found in Geographia, and astronomy not found in Almagest).

asolove 13y ago
Interesting, what do you mean he "understood he was in the Northern Hemisphere"? There are an infinite number of possible ways to divide a sphere into hemispheres, so how did he define the hemispheres and how did he describe the one he was in? Was he aware that the seasons were the result of the Earth's tilt and that they would be swapped in the other hemisphere as defined by that tilt? (I presume he didn't know that he was in the northern hemisphere because he thought he was closer to the northern magnetic pole.)
- einhverfr 13y ago
  If you read Tetrabiblos, he describes Africans (presumably from Nubia) as "burned by the sun" and explains this due to the fact that the "sun is over their heads." While the Africans are too dark, he doesn't think much of Northern Europeans either, who he says look sickly and pale because the bear is over their heads. Alexandria, being the center of the world, and neither too light nor too dark, nor too far East nor too far West, is best of course in his eyes. In Almagest he describes two things. The first is the shape of the earth, where he points out that it must be a sphere because of the changes in inclination of the moon and stars as you head North and South, and the changes in times of lunar eclipses when you head East to West. His descriptions of the rotation of the earth and the position of the sun relative to the earth leave no doubt that he was aware of Northern and Southern hemispheres. > Was he aware that the seasons were the result of the Earth's tilt and that they would be swapped in the other hemisphere as defined by that tilt? It's a little hard. Alexandria's sub-tropical. He does mention the inclination of the earth relative to the equator though, iirc, in Almagest.
igravious 13y ago
Top marks for Ptolemy (I think that's the more usual spelling in English?) citations. But I think the point is that the Northeren Hemisphere gets its northern-ness from magnetic north or the pole star, correct? But what makes north be up/top and south be down/under? Vile European hegemony I tells ya. I jest. But do I? Also, obligatory Gall-Peter's Projection reference for maximum egalitarian cred: http://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection http://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection . Choice quote for cartography newbs: "The Mercator projection increasingly inflates the sizes of regions according to their distance from the equator. This inflation results, for example, in a representation of Greenland that is larger than Africa, whereas in reality Africa is 14 times as large. Since much of the technologically underdeveloped world lies near the equator, these countries appear smaller on a Mercator and therefore, according to Peters, seem less significant. On Peters's projection, by contrast, areas of equal size on the globe are also equally sized on the map."
- einhverfr 13y ago
  Probably the pole star first, but given the various directions maps were drawn for so long, it's hard to say that was a factor in the Middle Ages or even Roman times.
- einhverfr 13y ago
  BTW, one interesting read regarding medieval maps and knowledge of geography is "Heaven and Earth in the Middle Ages: The Physical World before Colombus" by Rudolf Simek. It's expensive, so you may want to check libraries. However it is quite an impressive work, quite accessible, and deeply interesting. One of the more interesting points is that while Europeans were generally aware that the world was round since at least the 13th century (and monks from at least the 8th century) they thought it was impossible to sale across the equator until remarkably late. And the really revolutionary part of Columbus's voyages was that it destroyed the Augustinian view of people, since the Augustinian view was that if there were other continents, they must not be inhabited (because of only three sons of Noah meant only three inhabited continents).
  - igravious 13y ago

asolove 13y ago

Interesting, what do you mean he "understood he was in the Northern Hemisphere"? There are an infinite number of possible ways to divide a sphere into hemispheres, so how did he define the hemispheres and how did he describe the one he was in? Was he aware that the seasons were the result of the Earth's tilt and that they would be swapped in the other hemisphere as defined by that tilt? (I presume he didn't know that he was in the northern hemisphere because he thought he was closer to the northern magnetic pole.)

einhverfr 13y ago
If you read Tetrabiblos, he describes Africans (presumably from Nubia) as "burned by the sun" and explains this due to the fact that the "sun is over their heads." While the Africans are too dark, he doesn't think much of Northern Europeans either, who he says look sickly and pale because the bear is over their heads. Alexandria, being the center of the world, and neither too light nor too dark, nor too far East nor too far West, is best of course in his eyes. In Almagest he describes two things. The first is the shape of the earth, where he points out that it must be a sphere because of the changes in inclination of the moon and stars as you head North and South, and the changes in times of lunar eclipses when you head East to West. His descriptions of the rotation of the earth and the position of the sun relative to the earth leave no doubt that he was aware of Northern and Southern hemispheres. > Was he aware that the seasons were the result of the Earth's tilt and that they would be swapped in the other hemisphere as defined by that tilt? It's a little hard. Alexandria's sub-tropical. He does mention the inclination of the earth relative to the equator though, iirc, in Almagest.

igravious 13y ago

Top marks for Ptolemy (I think that's the more usual spelling in English?) citations. But I think the point is that the Northeren Hemisphere gets its northern-ness from magnetic north or the pole star, correct? But what makes north be up/top and south be down/under? Vile European hegemony I tells ya. I jest. But do I? Also, obligatory Gall-Peter's Projection reference for maximum egalitarian cred: http://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection http://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection . Choice quote for cartography newbs: "The Mercator projection increasingly inflates the sizes of regions according to their distance from the equator. This inflation results, for example, in a representation of Greenland that is larger than Africa, whereas in reality Africa is 14 times as large. Since much of the technologically underdeveloped world lies near the equator, these countries appear smaller on a Mercator and therefore, according to Peters, seem less significant. On Peters's projection, by contrast, areas of equal size on the globe are also equally sized on the map."

einhverfr 13y ago
Probably the pole star first, but given the various directions maps were drawn for so long, it's hard to say that was a factor in the Middle Ages or even Roman times.
einhverfr 13y ago
BTW, one interesting read regarding medieval maps and knowledge of geography is "Heaven and Earth in the Middle Ages: The Physical World before Colombus" by Rudolf Simek. It's expensive, so you may want to check libraries. However it is quite an impressive work, quite accessible, and deeply interesting. One of the more interesting points is that while Europeans were generally aware that the world was round since at least the 13th century (and monks from at least the 8th century) they thought it was impossible to sale across the equator until remarkably late. And the really revolutionary part of Columbus's voyages was that it destroyed the Augustinian view of people, since the Augustinian view was that if there were other continents, they must not be inhabited (because of only three sons of Noah meant only three inhabited continents).
- igravious 13y ago