The Wall as "Well"

Here's another curious detail to ponder in the "hard science" department. The Wall of Nessus is said to be leagues (plural) tall, where each league is three miles. That is some serious vertical terrain. If we take as true the PLAN[E]T ENGINEERING map suggestion that the diameter of the circle enclosing Nessus is twenty leagues (sixty miles), and we assume the Wall is two or three leagues high (six or nine miles), we could determine the lattitude of Nessus by the altitude of the presumed mossline growing on the northern wall where direct sunlight never falls. (Unless Nessus lies upon the tropic, and then the whole well would be briefly lit for a short while in summer.) The shadow of the Wall must be immense! Just as mountain valley communities have late sunrise and early sunset, so must Nessus experience truncated sunlight/enhanced dawn/dusk indirect lighting. (Is this another reason for the law forbidding buildings any closer to the Wall [leading to the Inn of Lost Loves being a treehouse]-- that there is a twilight zone of so many leagues?) The Sanguinary Field lies at the edge of the built up area, and their sennet trumpet is heard when the solar disk reaches the Wall. Well, gee, that could be as early as three o'clock, if at all! <g> Humans will find it hard to breath at heights greater than four miles above sea level. So watchers at the machicolations either have breathing gear (necklaces of air, or what-have-you) or they aren't standard issue humans. =mantis=

On the other hand, when Typhon is showing Severian the world from the eye, Nessus is described as spreading over many hundreds of leagues. You probably couldn't see the walls from the middle of the city. Peter.