Herr Thiessen's clock - In the novel Herr is asked to create a clock for someone. The clock is placed in the middle of the circus. This clock can represent how time is the center of the novel. It helps create a path for people, but sometimes people destroy it.
Ufansius Watch set into a single Colombian emerald crystal, circa 1600; the watch is part of the Cheapside Hoard, a cache of jewels and jewelry buried since the Great Fire of London in 1666 and rediscovered in 1912. More from the Hoard here, here, and here.
Moon phases. Looks to be old-style, not sure if it actually is old info, but fortunately for me, we've known most of what we need to know about the moon phases for several hundred years now. (Not, obviously, the mineral content, or many other vital facts about luna, until very recently... but none the less even if it were inaccurate old science is still interesting, even when not accurate.)