a device for measuring time in which sand or liquid runs through a narrow neck from an upper to a lower glass vessel

书桌上的滴漏计时器里的沙子正好能流十五分钟。

an ancient timekeeping device that measures time by the regulated flow of water or other liquid, also known as a clepsydra

古代中国的滴漏计时器通过观测水位的变化来测量时间。