3 ideas
In 1753 the London automaton-maker Alister Cox, still grieving his five-year-old daughter Abigail, travels to the Forbidden City at the Qianlong Emperor's summons and is asked to build clocks for particular kinds of lived time, such as a child's and a lover's. The commissions end with a perpetual clock driven by changes in atmospheric pressure, so the story moves from measuring human time toward measuring a time no one lives through.
Time is not one uniform flow but many durations that stretch or contract with the condition of the person living through them. The novel tests this by asking a mechanic to build a separate mechanism for each kind of lived time. The distance between clock time and felt time is exactly what the mechanisms try, and ultimately fail, to capture.
A ruler who commissions a clock that never stops is really asking for a material proof that some order can outlast death, his own included. The clock would keep running after its maker and its owner are gone. It would therefore measure a time no human can inhabit, which makes it a monument to mortality rather than a victory over it.