![E4CC appendix2](https://upload.wikimedia.org/wikipedia/commons/8/85/E4CC_appendix2.jpg)
An hourglass (or sandglass, sand timer, sand clock or egg timer) is a device used to measure the passage of
time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
. It comprises two
glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
bulbs connected vertically by a narrow neck that allows a regulated flow of a substance (historically
sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...
) from the upper bulb to the lower one. Typically, the upper and lower bulbs are symmetric so that the hourglass will measure the same duration regardless of orientation. The specific duration of time a given hourglass measures is determined by factors including the quantity and coarseness of the particulate matter, the bulb size, and the neck width.
Depictions of an hourglass as a symbol of the passage of time are found in art, especially on tombstones or other monuments, from antiquity to the present day. The form of a winged hourglass has been used as a literal depiction of the well-known idiom "
time flies
Time Flies may refer to:
* '' Tempus fugit'', a Latin phrase usually translated as "time flies"; an admonition against procrastination
Film
* ''Time Flies'' (1944 film), a British comedy directed by Walter Forde
* ''Time Flies'' (2013 film), a ...
".
History
Antiquity
![Peleus-Thetis-350](https://upload.wikimedia.org/wikipedia/commons/a/a2/Peleus-Thetis-350.jpg)
The origin of the hourglass is unclear. Its predecessor the
clepsydra, or
water clock
A water clock or clepsydra (; ; ) is a timepiece by which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel, and where the amount is then measured.
Water clocks are one of the oldest time-m ...
, is known to have existed in
Babylon
''Bābili(m)''
* sux, 𒆍𒀭𒊏𒆠
* arc, 𐡁𐡁𐡋 ''Bāḇel''
* syc, ܒܒܠ ''Bāḇel''
* grc-gre, Βαβυλών ''Babylṓn''
* he, בָּבֶל ''Bāvel''
* peo, 𐎲𐎠𐎲𐎡𐎽𐎢 ''Bābiru''
* elx, 𒀸𒁀𒉿𒇷 ''Babi ...
and
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
as early as the 16th century BC.
Early Middle Ages
![Ambrogio Lorenzetti 002-detail-Temperance](https://upload.wikimedia.org/wikipedia/commons/0/0f/Ambrogio_Lorenzetti_002-detail-Temperance.jpg)
There are no records of the hourglass existing in Europe prior to the
Early Middle Ages
The Early Middle Ages (or early medieval period), sometimes controversially referred to as the Dark Ages, is typically regarded by historians as lasting from the late 5th or early 6th century to the 10th century. They marked the start of the Mi ...
; the first documented example dates from the 8th century AD, crafted by a
Frankish
Frankish may refer to:
* Franks, a Germanic tribe and their culture
** Frankish language or its modern descendants, Franconian languages
* Francia, a post-Roman state in France and Germany
* East Francia, the successor state to Francia in Germany ...
monk named Liutprand who served at the cathedral in
Chartres, France
Chartres () is the Prefectures in France, prefecture of the Eure-et-Loir Departments of France, department in the Centre-Val de Loire Regions of France, region in France. It is located about southwest of Paris. At the 2019 census, there were 1 ...
.
But 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 (; – 9 June 1348) or Ambruogio Laurati was an Italian painter of the Sienese school. He was active from approximately 1317 to 1348. He painted ''The Allegory of Good and Bad Government'' in the Sala dei Nove (Salon of Nine ...
.
Use of the marine sandglass has been recorded since the 14th century. The written records about it were mostly from logbooks of European ships.
In the same period it appears in other records and lists of ships stores. The earliest recorded reference that can be said with certainty to refer to a marine sandglass dates from c. 1345, in a receipt of Thomas de Stetesham, clerk of the King's ship ''La George'', in the reign of
Edward III
Edward III (13 November 1312 – 21 June 1377), also known as Edward of Windsor before his accession, was King of England and Lord of Ireland from January 1327 until his death in 1377. He is noted for his military success and for restoring r ...
of England; translated from the Latin, the receipt says: 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 9''s.'' Item, For four horologes of the same sort (" de eadem secta "), bought there, price of each five gross', making in sterling 3''s.'' 4''d.''"
Marine sandglass
A marine sandglass is a timepiece of simple design that is a relative of the common hourglass, a marine (nautical) instrument known since the 14th century (although reasonably presumed to be of very ancient use and origin). Sandglasses were used t ...
es 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.
[Balmer, R.T. "The Operation of Sand Clocks and Their Medieval Development." Technology and Culture, Vol. 19, No. 4 (Oct., 1978), pp. 615-632.] Seamen found that the hourglass was able to help them determine a ship's speed. They would tie a knot every 40-50 feet in a line, tie it to a log, toss the log into the water, then count how many knots slipped through their fingers in the interval measured by the glass. An accurate clock would also have enabled a seaman to determine
longitude
Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...
, distance east or west from a certain point, but an error of four minutes would correspond to one degree of longitude, or some 70 statute miles, so it's doubtful whether an hourglass ever made this practical.
The hourglass also found popularity on land. 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, 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. The oldest known surviving hourglass resides in the
British Museum
The British Museum is a public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is among the largest and most comprehensive in existence. It docum ...
in London.
Not until the 18th century did
John Harrison
John Harrison ( – 24 March 1776) was a self-educated English Carpentry, carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the History of longitude, problem of calculating longitude while at s ...
come up with a
marine chronometer
A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT), or in the modern ...
that significantly improved on the stability of the hourglass at sea. Taking elements from the design logic behind the hourglass, he made a marine chronometer in 1761 that was able to accurately measure the journey from England to Jamaica accurate within five seconds.
Design
Little written evidence exists to explain 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
An ampoule (also ampul and ampule) is a small sealed vial which is used to contain and preserve a sample, usually a solid or liquid. Ampoules are usually made of glass.
Modern ampoules are most commonly used to contain pharmaceuticals and chem ...
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.
Material
While some early hourglasses actually did use
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
sand as the granular material to measure time, many did not use sand at all. The material used in most bulbs was "powdered
marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or Dolomite (mineral), dolomite. Marble is typically not Foliation (geology), foliated (layered), although there are exceptions. In geology, the ...
,
tin
Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal.
Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...
/
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
oxides,
rpulverized, 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
![Egg timer](https://upload.wikimedia.org/wikipedia/commons/4/49/Egg_timer.jpg)
Hourglasses were an early dependable 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, hourglasses 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 ( or ; pt, Fernão de Magalhães, ; es, link=no, Fernando de Magallanes, ; 4 February 1480 – 27 April 1521) was a Portuguese explorer. He is best known for having planned and led the 1519 Spanish expedition to the East ...
around the globe, 18 hourglasses from Barcelona were in the ship's inventory, after the trip had been authorized by King
Charles I of Spain
Charles V, french: Charles Quint, it, Carlo V, nl, Karel V, ca, Carles V, la, Carolus V (24 February 1500 – 21 September 1558) was Holy Roman Emperor and Archduke of Austria from 1519 to 1556, King of Spain ( Castile and Aragon) fro ...
.
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
The zenith (, ) is an imaginary point directly "above" a particular location, on the celestial sphere. "Above" means in the vertical direction (plumb line) opposite to the gravity direction at that location (nadir). The zenith is the "highest" ...
.
A number of sandglasses could be fixed in a common frame, each with a different operating time, e.g. as in a four-way Italian sandglass likely from the 17th century, in the collections of the Science Museum, in South Kensington, London, which could measure intervals of quarter, half, three-quarters, and one hour (and which were also used in churches, for priests and ministers to measure lengths of sermons).
Modern practical uses
![Budapest timewheel 02](https://upload.wikimedia.org/wikipedia/commons/1/17/Budapest_timewheel_02.jpg)
While they are no longer widely used for keeping time, some institutions do maintain them. Both houses of the
Australian Parliament
The Parliament of Australia (officially the Federal Parliament, also called the Commonwealth Parliament) is the legislature, legislative branch of the government of Australia. It consists of three elements: the monarch (represented by the ...
use three hourglasses to
time certain procedures, such as
divisions.
The sandglass is still widely used as the kitchen
egg timer
An egg timer or kitchen timer is a device whose primary function is to assist in timing during cooking; the name comes from the first timers initially being used for the timing of cooking eggs. Early designs simply counted down for a specific per ...
; 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'' (, ) is a charades-inspired word-guessing game invented by Robert Angel with graphic design by Gary Everson and first published in 1985 by Angel Games Inc. Angel Games licensed Pictionary to Western Publishing. Hasbro purchas ...
and
Boggle
''Boggle'' is a word game invented by Allan Turoff and originally distributed by Parker Brothers. The game is played using a plastic grid of lettered dice, in which players look for words in sequences of adjacent letters.
Rules
One player begi ...
to implement a time constraint on rounds of play.
Symbolic uses
![Flag of Christopher Moody](https://upload.wikimedia.org/wikipedia/commons/5/5f/Flag_of_Christopher_Moody.svg)
Unlike most other methods of measuring time, the hourglass concretely represents the present as being between the
past
The past is the set of all events that 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 t ...
and the
future
The future is the time after the past and present. Its arrival is considered inevitable due to the existence of time and the laws of physics. Due to the apparent nature of reality and the unavoidability of the future, everything that currently ...
, 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.
[ "Time is getting short; there will be little opportunity to do what you have to do unless you take the chance now. The phrase is often used with reference to one who has not much longer to live. The allusion is to the hourglass."] It was used thus on
pirate
Piracy is an act of robbery or criminal violence by ship or boat-borne attackers upon another ship or a coastal area, typically with the goal of stealing cargo and other valuable goods. Those who conduct acts of piracy are called pirates, v ...
flags, to strike fear into the hearts of the pirates' victims. In England, hourglasses were sometimes placed in coffins,
[ "Hour-glasses were formerly placed in coffins and buried with the corpse, probably as symbols of mortality—the sands of life having run out. See Gent. Mag. vol xvi, 646, and xvii, 264."] and they have graced gravestones for centuries. The hourglass was also used in
alchemy
Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim world, ...
as a symbol for
hour
An hour (symbol: h; also abbreviated hr) is a unit of time conventionally reckoned as of a day and scientifically reckoned between 3,599 and 3,601 seconds, depending on the speed of Earth's rotation. There are 60 minutes in an hour, and 24 ho ...
.
The former
Metropolitan Borough of Greenwich
The Metropolitan Borough of Greenwich was a Metropolitan boroughs of the County of London, metropolitan borough in the County of London between 1900 and 1965. It bordered the boroughs of Metropolitan Borough of Woolwich, Woolwich, Metropolitan B ...
in
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
used an hourglass on its coat of arms, symbolising Greenwich's role as the origin of
GMT
Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a cons ...
. The district's successor, the
Royal Borough of Greenwich
The Royal Borough of Greenwich (, , or ) is a London borough in southeast Greater London. The London Borough of Greenwich was formed in 1965 by the London Government Act 1963. The new borough covered the former area of the Metropolitan Borough ...
, uses two hourglasses on its
coat of arms
A coat of arms is a heraldry, heraldic communication design, visual design on an escutcheon (heraldry), escutcheon (i.e., shield), surcoat, or tabard (the latter two being outer garments). The coat of arms on an escutcheon forms the central ele ...
.
Modern symbolic uses
![Cursor-design1-hourglass](https://upload.wikimedia.org/wikipedia/commons/7/73/Cursor-design1-hourglass.svg)
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'' (also stylized as ''Days of our Lives''; simply referred to as ''Days'' or ''DOOL'') is an American television soap opera that streams on the streaming service Peacock. The soap, which aired on the American television net ...
'', 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
Edward Macdonald Carey (March 15, 1913 – March 21, 1994) was an American actor, best known for his role as the patriarch Dr. Tom Horton on NBC's soap opera ''Days of Our Lives''. For almost three decades, he was the show's central cast member.
...
.
Various computer
graphical user interface
The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
s may change the
pointer to an
hourglass
An hourglass (or sandglass, sand timer, sand clock or egg timer) is a device used to measure the passage of time. It comprises two glass bulbs connected vertically by a narrow neck that allows a regulated flow of a substance (historically sand) ...
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
In computer programming, an infinite loop (or endless loop) is a sequence of instructions that, as written, will continue endlessly, unless an external intervention occurs ("pull the plug"). It may be intentional.
Overview
This differs from:
* ...
and needs to be terminated, or is waiting for some external event (such as the user inserting a CD).
Unicode
Unicode, formally The Unicode Standard,The formal version reference is is an information technology Technical standard, standard for the consistent character encoding, encoding, representation, and handling of Character (computing), text expre ...
has an
HOURGLASS symbol at
U+231B
(⌛).
Hourglass motif
![hourglass-cross](https://upload.wikimedia.org/wikipedia/commons/c/c2/Hourglass-cross.png)
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
Thunderbird, thunder bird or thunderbirds may refer to:
* Thunderbird (mythology), a legendary creature in certain North American indigenous peoples' history and culture
* Ford Thunderbird, a car
Birds
* Dromornithidae, extinct flightless birds ...
or (in more elongated form) an enemy scalp, and in South America, where it 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
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
examples can be seen among Spanish
cave paintings
In archaeology, Cave paintings are a type of parietal art (which category also includes petroglyphs, or engravings), found on the wall or ceilings of caves. The term usually implies prehistoric art, prehistoric origin, and the oldest known are mor ...
. 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
Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capita ...
.
[Craig, Barr]
A Stone Tablet from Buka Island
in ''Archaeological Studies of the Middle and Late Holocene, Papua New Guinea (Technical Report 20)'' (ed. Specht, Jim & Attenbrow, Val) Australian Museum (2007) Both the members of Project Tic Toc, from television series the
Time Tunnel
''The Time Tunnel'' is an American color science fiction TV series written around a theme of time travel adventure starring James Darren and Robert Colbert. The show was creator-producer Irwin Allen's third science-fiction television series and ...
and the
Challengers of the Unknown
The Challengers of the Unknown is a fictional group of adventurers appearing in comic books published by DC Comics. The quartet of adventurers explored paranormal occurrences while facing several fantastic menaces.
The characters' provenance is ...
use symbols of the hourglass representing either time travel or time running out.
File:Livingstone Mausoleum detail - geograph.org.uk - 1325673.jpg, 17thC tombstone in the mausoleum of John Livingstone, 'an apothecary in Edinburgh', who fell victim to the plague 1645
File:Knochenmann in Salzburg.JPG, Tomb in the , Salzburg
Salzburg (, ; literally "Salt-Castle"; bar, Soizbuag, label=Bavarian language, Austro-Bavarian) is the List of cities and towns in Austria, fourth-largest city in Austria. In 2020, it had a population of 156,872.
The town is on the site of the ...
File:DeHe vanitas-conocete-a-ti-mismo-jacobo-jordaens-rennes-MBA.jpg, ''Know thyself
The Ancient Greek aphorism "know thyself" (Greek: , transliterated: '; also ' with the ε contracted) is the first of three Delphic maxims inscribed in the forecourt of the Temple of Apollo at Delphi according to the Greek writer Pausanias ...
- Youth between Vice and Virtue'' (attributed to Jacob Jordaens
Jacob (Jacques) Jordaens (19 May 1593 – 18 October 1678) was a Flemish painter, draughtsman and tapestry designer known for his history paintings, genre scenes and portraits. After Peter Paul Rubens and Anthony van Dyck, he was the leading Fle ...
)
File:StillLifeWithASkull.jpg, Philippe de Champaigne
Philippe de Champaigne (; 26 May 1602 – 12 August 1674) was a Brabançon-born French Baroque era painter, a major exponent of the French school. He was a founding member of the Académie de peinture et de sculpture in Paris, the premier art ...
''Still-Life with a Skull'', vanitas
A ''vanitas'' (Latin for 'vanity') is a symbolic work of art showing the transience of life, the futility of pleasure, and the certainty of death, often contrasting symbols of wealth and symbols of ephemerality and death. Best-known are ''van ...
painting, 1671
File:Self-portrait (with Hourglass and Skull) by Johann Zoffany.jpg, ''Self-portrait'' (with hourglass and skull) by Johann Zoffany
Johan Joseph Zoffany (born Johannes Josephus Zaufallij; 13 March 1733 – 11 November 1810) was a German neoclassical painter who was active mainly in England, Italy and India. His works appear in many prominent British collections, includin ...
, circa 1776
See also
*
List of largest hourglasses
*
Marine sandglass
A marine sandglass is a timepiece of simple design that is a relative of the common hourglass, a marine (nautical) instrument known since the 14th century (although reasonably presumed to be of very ancient use and origin). Sandglasses were used t ...
*
Water clock
A water clock or clepsydra (; ; ) is a timepiece by which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel, and where the amount is then measured.
Water clocks are one of the oldest time-m ...
*
Hourglass figure
The hourglass figure is one of four traditional female body shapes described by the fashion industry. The other shapes are the rectangular, inverted triangle, and spoon/pear. The hourglass shape is defined by a woman's body measurements- the circum ...
References
Further reading
Books
*
*
*
*
Periodicals
*
*
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