art of constructing sundials or clocks
• (n.) An account of the hours. • (n.) The art of constructing instruments for making the hours, as clocks, watches, and dials.
Ho·rog'ra·phy noun [ Greek ... hour + -graphy : confer French horographie .] 1. An account of the hours. Chaucer. 2. The art of constructing instruments for making the hours, as clocks, watches, and dials. 
horography Writing about time and timekeeping instruments.