Levine writes, “The Chinese developed an incense clock. This wooden device consisted of a series of connect small same-sized boxes. Each box held a different fragrance of incense. By knowing the time it took for a box to burn its supply, and the order in which the scents burned, observers could recognize the time of day by the smell in the air.”

Not quite a “clock,” though, since Levine later notes that the work clock is “derived from Middle Dutch and German words for bell,” since the earliest clocks were designed to ring bells at liturgical hours.