An hourglass measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically common hour timing. Factors affecting the time measured include the amount of sand, the bulb size, the neck width, and the sand quality. Alternatives to sand are powdered eggshell and powdered marble (sources disagree on the best material). In modern times, hourglasses are ornamental, or used when an approximate measure suffices, as in egg timers for cooking or for board games.

History

The origin of the hourglass is unclear, although it may have been introduced to Europe by an 8th-century monk named Luitprand, who served at the cathedral in Chartres, France. It was not until the 14th century that the hourglass was seen commonly, the earliest firm evidence being a depiction in the 1338 fresco Allegory of Good Government by Ambrogio Lorenzetti

Ambrogio Lorenzetti

Ambrogio Lorenzetti was an Italian painter of the Sienese school. He was active between approximately 1317 to 1348. His elder brother was the painter Pietro Lorenzetti....

. Unlike its predecessor the clepsydra

Water clock

A water clock or clepsydra is any timepiece in which time is measured by the regulated flow of liquid into or out from a vessel where the amount is then measured.Water clocks, along with sundials, are likely to be the oldest time-measuring instruments, with the only exceptions...

, or water clock

Water clock

A water clock or clepsydra is any timepiece in which time is measured by the regulated flow of liquid into or out from a vessel where the amount is then measured.Water clocks, along with sundials, are likely to be the oldest time-measuring instruments, with the only exceptions...

, which may have been invented in ancient Egypt, the hourglass is believed to have originated in medieval Europe. This theory is based on the fact that the first written records of it were mostly from logbooks of European ships. Written records from the same period mention the hourglass, and it appears in lists of ships stores. An early record is a sales receipt of Thomas de Stetesham, clerk of the English ship La George, in 1345:

"The same Thomas accounts to have paid at Lescluse, in Flanders, for twelve glass horologes (" pro xii. orlogiis vitreis "), price of each 4½ gross', in sterling 9s. Item, For four horologes of the same sort (" de eadem secta "), bought there, price of each five gross', making in sterling 3s. 4d."

Hourglasses were very popular on board ships, as they were the most dependable measurement of time while at sea. Unlike the clepsydra, the motion of the ship while sailing did not affect the hourglass. The fact that the hourglass also used granular materials instead of liquids gave it more accurate measurements, as the clepsydra was prone to get condensation inside it during temperature changes. Seamen found that the hourglass was able to help them determine longitude, distance east or west from a certain point, with reasonable accuracy.

The hourglass also found popularity on land as well. As the use of mechanical clocks to indicate the times of events like church services became more common, creating a ‘need to keep track of time’, the demand for time-measuring devices increased. Hourglasses were essentially inexpensive, as they required no rare technology to make and their contents were not hard to come by, and as the manufacturing of these instruments became more common, their uses became more practical.

Hourglasses were commonly seen in use in churches, homes, and work places to measure sermons, cooking time, and time spent on breaks from labor. Because they were being used for more everyday tasks, the model of the hourglass began to shrink. The smaller models were more practical and very popular as they made timing more discreet.

After 1500 A.D., the hourglass was not as widespread as it had been. This was due to the development of the mechanical clock, which became more accurate, smaller and cheaper, and made keeping time easier. The hourglass, however, did not disappear entirely. Although they became relatively less useful as clock technology advanced, hourglasses remained desirable in their design. Some of the most famous hourglasses are the twelve-hour hourglass of Charlemagne of France and the hourglasses of Henry the VIII of England, made by the artist Holbein in the 16th century. The oldest known surviving hourglass resides in the British Museum in London.

Not until the 18th century did the Harrison brothers, John and James, come up with a marine chronometer

Marine chronometer

A marine chronometer is a clock that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determine longitude by means of celestial navigation...

 that significantly improved on the stability of the hourglass at sea. Taking elements from the design logic behind the hourglass, they were able to invent a marine chronometer that was able to accurately measure the journey from England to Jamaica, with only a miscalculation of five seconds, in 1761.

Design

The shape behind the hourglass has hardly any written evidence of why its external form is the shape that it is. The glass bulbs used, however, have changed in style and design over time. While the main designs have always been ampoule in shape, the bulbs were not always connected. The first hourglasses were two separate bulbs with a cord wrapped at their union that was then coated in wax to hold the piece together and let sand flow in between. It was not until 1760 that both bulbs were blown together to keep moisture out of the bulbs and regulate the pressure within the bulb that varied the flow of the granular substance.

Material

While some hourglasses actually did use sand as the granular mixture to measure time, many did not use sand at all. The material used in most bulbs was a combination of “powdered marble, tin/lead oxides, and pulverized, burnt eggshell”. Over time, different textures of granule matter were tested to see which gave the most constant flow within the bulbs. It was later discovered that for the perfect flow to be achieved the ratio of granule bead to the width of the bulb neck needed to be 1/12 or more but not greater than 1/2 the neck of the bulb.

Practical uses

Hourglasses were an early dependable, reusable and accurate measure of time. The rate of flow of the sand is independent of the depth in the upper reservoir, and the instrument will not freeze in cold weather.

From the 15th century onwards, they were being used in a range of applications at sea, in the church, in industry and in cookery.

During the voyage of Ferdinand Magellan

Ferdinand Magellan

Ferdinand Magellan was a Portuguese explorer. He was born in Sabrosa, in northern Portugal, and served King Charles I of Spain in search of a westward route to the "Spice Islands" ....

 around the globe, his vessels kept 18 hourglasses per ship. It was the job of a ship's page to turn the hourglasses and thus provide the times for the ship's log. Noon was the reference time for navigation, which did not depend on the glass, as the sun would be at its zenith

Zenith

The zenith is an imaginary point directly "above" a particular location, on the imaginary celestial sphere. "Above" means in the vertical direction opposite to the apparent gravitational force at that location. The opposite direction, i.e...

. More than one hourglass was sometimes fixed in a frame, each with a different running time, for example 1 hour, 45 minutes, 30 minutes, and 15 minutes.

Modern practical uses

While they are no longer widely used for keeping time, some institutions do maintain them. Both houses of the Australian Parliament use three hourglasses to time certain procedures, such as divisions.

The sandglass is still widely used as the kitchen egg timer

Egg timer

An egg-timer is a device the primary function of which is to assist in timing the cooking of eggs. Early designs simply counted down for a specific period of time. Some modern designs are able to time more accurately by depending on water temperature rather than an absolute time...

; for cooking eggs, a three minute timer is typical, hence the name "egg timer" for three minute hourglasses. Egg timers are sold widely as souvenirs.
Sand timers are also sometimes used in games such as Pictionary

Pictionary

Pictionary is a guessing word game designed by Robert Angel and first published in 1985 by Seattle Games Inc. The game is played with teams with players trying to identify specific words from their teammates' drawings.-Objective:...

 and Boggle

Boggle

Boggle is a word game designed by Allan Turoff and trademarked by Parker Brothers, a division of Hasbro. The game is played using a plastic grid of lettered dice, in which players attempt to find words in sequences of adjacent letters.-Rules:...

 to implement a time constraint on rounds of play, and provide a sense of urgency to the game of Quicksand

Quicksand (1981 board game)

Quicksand is a board game produced in 1981 by the Whitman Publishing Company. It should not be confused with the 1989 Parker Brothers board game of the same name...

.

Symbolic uses

Unlike most other methods of measuring time, the hourglass concretely represents the present as being between the past

Past

Most generally, the past is a term used to indicate the totality of events which occurred before a given point in time. The past is contrasted with and defined by the present and the future. The concept of the past is derived from the linear fashion in which human observers experience time, and is...

 and the future

Future

The future is the indefinite time period after the present. Its arrival is considered inevitable due to the existence of time and the laws of physics. Due to the nature of the reality and the unavoidability of the future, everything that currently exists and will exist is temporary and will come...

, 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 thus 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

Alchemy

Alchemy is an influential philosophical tradition whose early practitioners’ claims to profound powers were known from antiquity. The defining objectives of alchemy are varied; these include the creation of the fabled philosopher's stone possessing powers including the capability of turning base...

 as a symbol for hour

Hour

The hour is a unit of measurement of time. In modern usage, an hour comprises 60 minutes, or 3,600 seconds...

.

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

Days of our Lives

Days of our Lives is a long running daytime soap opera broadcast on the NBC television network. It is one of the longest-running scripted television programs in the world, airing nearly every weekday in the United States since November 8, 1965. It has since been syndicated to many countries around...

, 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

Macdonald Carey

Edward Macdonald Carey was an American actor, best known for his role as the patriarch Dr. Tom Horton on NBC's soap opera Days of our Lives...

.

Various computer programs and earlier versions of Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 may change the mouse cursor

Cursor (computers)

In computing, a cursor is an indicator used to show the position on a computer monitor or other display device that will respond to input from a text input or pointing device. The flashing text cursor may be referred to as a caret in some cases...

 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 a Windows hourglass does not disappear, it suggests a program is in an infinite loop

Infinite loop

An infinite loop is a sequence of instructions in a computer program which loops endlessly, either due to the loop having no terminating condition, having one that can never be met, or one that causes the loop to start over...

 and needs to be terminated, or is waiting for some external event (such as the user inserting a CD). Unicode

Unicode

Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 has an HOURGLASS symbol at U+231B .

Hourglass motif

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

Indigenous peoples of the Americas

The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...

 art; both in North America, where it can represent, for example, the body of the Thunderbird

Thunderbird (mythology)

The Thunderbird is a legendary creature in certain North American indigenous peoples' history and culture. It is considered a "supernatural" bird of power and strength...

 or (in more elongated form) an enemy scalp, and in South America, where it is believed to represent a Chuncho

Chuncho

The Chuncho are a native ethnic group in South America. At the time of the Spanish conquest the Chuncho lived in the forests east of Cuzco, in central Peru and dwelled in communal houses living chiefly by hunting. Chuncho has also been used to describe one of three aboriginal stocks of Peru, the...

 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

Neolithic

The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...

 examples can be seen among Spanish

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 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.

Hourglass body shape

Hourglass also refers to a body shape

Body shape

Human body shape is a complex phenomenon with sophisticated detail and function. The general shape or figure of a person is defined mainly by skeletal structure, muscles and fat...

 of women

Female body shape

Female body shape or figure is the cumulative product of a woman's skeletal structure and the quantity and distribution of muscle and fat on the body. There are, and have been, wide differences on what should be considered an ideal or preferred body shape, both for attractiveness and for health...

. In this shape bust and hip are significantly large with narrow waist resembling the shape of an hourglass. A common measurement of shape is 36 24 36 (size in inches). Even clothes to hug body of hourglass shape are available such as an hourglass corset

Hourglass corset

The hourglass corset produces a silhouette resembling the hourglass shape: wide bottom, narrow waist , wide top.-History:The first fashions worn with hourglass corsets, around 1830, emphasized width - they tended to have very wide skirts, large sleeves and sloping shoulders. These elements...

.

Further reading

Books

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