This is an example of outflow clepsydra. A commonly used water clock was the simple outflow clepsydra. Species such as "Aeshna clepsydra" and "Carterocephalus palaemon mandan" have been observed in its vicinity. The word "clepsydra" comes from the Greek meaning "water thief". Shen is credited with making improved designs of the gnomon, armillary sphere, and clepsydra clock. The clepsydra, or water clock, was the most prevalent of time-keeping devices for astronomers. Other Conjoiner characters, such as Remontoire and Clepsydra, also have meaningful names. Unbeknownst to him, however, Gaffney kills Clepsydra and frames Dreyfus. One of them, Clepsydra, has escaped and is hiding. However, the most common type of public and palace timekeeping device was the inflow clepsydra. Unlike the clepsydra, the motion of the ship while sailing did not affect the hourglass. A clepsydra is a clock that measures time by the flow of water. The clepsydra was also used as the official state time-keeping device. The clepsydra does not work today because only the water holding vessels have survived. Clepsydra is taken into isolation, whilst Dreyfus explains the situation to the Senior Prefects.