This is a water clock.
Yes, it is.
A water clock, or clepsydra [KLEP-si-druh], is an ancient means of keeping time, ancient enough we will probably not know its origins. A clepsydra works by the steady descent of water from a higher basin to a lower one. Drip, drip, drip. One basin empties, the other fills. Even now, in our digital age of vibrating quartz crystals and resonating cesium atoms, a clepsydra is perfectly good for the occasion when you don’t care so much what time it is as how much time has passed.
So when would you use such a clock?
In lambing season, my friends.
The thing is, a shepherd feels a certain obligation to check on the girls regularly during the night. But you can’t stay up all night waiting for lambs. It’s tough on bed partners to have the alarm going off every two or three hours during sleep time and, after all, only one shepherd has to get up to go out and look for little strangers in the sheepfold. After our first lambing season, in which we slept surrounded by alarm clocks, I came up with a better method. The gentle, reliable water clock has never failed me.
In this case, the drinking glass is the upper basin of the clock. I am the lower one. A full glass of water taken before hitting the mattress, and sleep comes easily. Two hours later, I am up again. I check the sheep, reset the water clock, and go back to bed. It still means getting up in the night. But there are no alarms ringing, no jolting awake in the wee hours, no grumpy partner muttering in disturbed dreams.
I recommend the ancient clepsydra for dependable timekeeping.