twitter 4(&5?)
My absolute favorite thing about The Book of the New Sun is its concept of time (Mainly because I discovered it all by myself). In the appendix to Claw, Gene Wolfe described the concept of a Watch, representing how long between the nightly watch is changed: 1/10th of the night, or 75 minutes.
What he doesn't connect is the fact that 10 watches adds up to 12.5 hours. Since the sun is dying, it has reached the point where the daylight lasts for less than half the day (for example, from 5 am to 4:30 pm) Absolutely brilliant way to convey this information.