It is an instrument for measuring time that consists of two glass crystals on top of each other connected by a narrow opening.  A full hour, half an hour, or a shorter period of time.

 Some of the bangalum (hourglass) was used to determine the amount of time the speaker had to give his speech.  Until the beginning of the twentieth century, sailors used an instrument, similar to an hourglass, that measured a duration of less than a minute.  With this tool they could measure the speed of ships. The hourglass was widely used before the invention of clocks of all kinds. However, it was replaced by small and large clocks, hand, wall, water, etc. Hourglass was mentioned by many writers as an expression of the passage of time.

 The hourglass is not a high-precision measuring instrument, the flow of sand from the upper crystal to the lower one is related to several factors, including:

 Smoothness and softness of sand.

 shape of crystals.

 The size of the opening between the two chambers and the degree to which it is affected by the passage of sand.

 clock stability.

 The vertical stand of the watch.

 Who invented the clock?

 The clock and in general in itself is unknown because the clock has changed its shape and work with it over time and civilizations. Some say that the first people who invented the hourglass were the Palmyrenes, others say that they are the Arabs and the Pharaohs, and some say that the prophet of God Noah was the first to put the twelve-hour system for timing  Night and day.. But it is mentioned that the first people who invented the system of calculating in minutes were the Babylonians, the first who invented the pendulum clock ((Christian Huygens)), and the first who invented the clock by Ibn Yunus al-Masry.. And the clock has been known since ancient times to the Arabs as the hourglass, and we can say  The inventor of the pocket watch is Hale in 1500 AD, the inventor of the chronograph is Bondi in 1885 AD, and the inventor of the wrist watch is Louis Cartier in 1904.

Nosebah Al-Shdefat