A coconut clepsydra, i.e. a water clock, that consists of a deep pot filled with water and a coconut shell bowl with a small hole in the center, that is put on the surface and slowly takes on water, filling the shell and making it sink ever deeper into the pot.

When it is full of water and begins to submerge, the coconut shell is lifted from the water, emptied and the process can be repeated, similar to the use of an hourglass. It is today still used by gold beaters in Mandalay to measure the passage of time  (fig.).