The Hourglass
The Hourglass is a device for the measurement of time.
It consists of two glass bulbs placed one above the other which are connected by a narrow tube. The hourglass is named for the most frequently used sandglass, where the sands have a running time of one hour.
Hourglasses are said to have been invented at Alexandria about the middle of the third century. It is speculated that it was in use in the 11th century, where it would have complemented the magnetic compass as an aid to navigation. Recorded evidence of their existence is found no earlier than the 14th century.
Finally, Hourglasses are still in use, but typically only ornamentally or when a relatively approximate measurement of time is needed, as in egg timers for cooking or board games.
It consists of two glass bulbs placed one above the other which are connected by a narrow tube. The hourglass is named for the most frequently used sandglass, where the sands have a running time of one hour.
Hourglasses are said to have been invented at Alexandria about the middle of the third century. It is speculated that it was in use in the 11th century, where it would have complemented the magnetic compass as an aid to navigation. Recorded evidence of their existence is found no earlier than the 14th century.
Finally, Hourglasses are still in use, but typically only ornamentally or when a relatively approximate measurement of time is needed, as in egg timers for cooking or board games.
The sundial
A sundial is a device that measures time by the position of the sun. As the sun moves across the sky, the shadow-edge progressively aligns with different hour-lines on the plate.
The first sundial that humans invented was by Obelisk in ancient Egypt in 3500 BC. With time, it became more specific and efficient, but even now, we can't know what is the exact hour from the Sundial.
In conclusion, the Sundial was one of the first clocks that was invented in
the world. Now there is no use in the sundial.
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