Automatic control of water level using a float level was used in the Middle East for a water clock [1, 11]. The water clock (Figure P1.11) was used from sometime before Christ until the 17th century. Discuss the operation of the water clock, and establish how the float provides a feedback control that maintains the accuracy of the clock. Sketch a block diagram of the feedback system.

Orlnece FIGURE P1.11 Water clock. From Newtn, Gould, and Kaiser. Analytical Design of Linear Feedback Controls. Wiley, New York, 1957, with pemission.)