Unlike most other methods of measuring time, the hourglass concretely represents the present as being between the past and the future, and this has made it an enduring symbol of time itself.
The hourglass, sometimes with the addition of metaphorical wings, is often depicted as a symbol that human existence is fleeting, and that the “sands of time” will run out for every human life.
It was used on pirate flags to strike fear into the hearts of the pirates’ victims. In England, hourglasses were sometimes placed in coffins, and they have graced gravestones for centuries. The hourglass was also used in alchemy as a symbol for an hour.
The hourglass shape is seen in cultures that never encountered it.
Because of its symmetry, graphic signs resembling an hourglass are seen in the art of cultures which never encountered such objects. Vertical pairs of triangles joined at the apex are common in Native American art; both in North America, where it can represent, for example, the body of the Thunderbird or (in more elongated form) an enemy scalp.
In South America, the hourglass motif is believed to represent a Chuncho jungle dweller.
In Zulu textiles, they symbolise a married man, as opposed to a pair of triangles joined at the base, which symbolise a married woman.
Neolithic examples can be seen among Spanish cave paintings. Observers have even given the name “hourglass motif” to shapes which have more complex symmetry, such as a repeating circle and cross pattern from the Solomon Islands.
Modern symbolic uses
Recognition of the hourglass as a symbol of time has survived its obsolescence as a timekeeper. For example, the American television soap opera Days of our Lives, since its first broadcast in 1965, has displayed an hourglass in its opening credits, with the narration, “Like sands through the hourglass, so are the days of our lives,” spoken by Macdonald Carey.
Various computer graphical user interfaces may change the pointer to an hourglass during a period when the program is in the middle of a task, and may not accept user input. During that period other programs, for example in different windows, may work normally.
When such an hourglass does not disappear, it suggests a program is in an infinite loop and needs to be terminated, or is waiting for some external event, such as the user inserting a CD. Unicode has an HOURGLASS symbol at