Possible Clues:

• What flows when measuring unusually dry places?
• Dry places, not right for this to work
• Water clock
• It won't work in dry places, unfortunately
• Old device with leaking water that would ruin dry places
• Ancient water clock
• New CD players no longer used timer
• Water-clock Percy's lad designed
• It measures time by the trickling of water
• Dry places damaged this timekeeper