An astrolabe (Ancient Greek: ἀστρολάβος astrolabos; Arabic: ٱلأَسْطُرلاب‎ al-Asturlāb; Persian: ستاره‌یاب‎ Setāreyāb) is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclinometer and an analogue calculation device capable of working out several kinds of problems in astronomy. Historically used by astronomers, it is able to measure thealtitudeabove the horizon of a celestial body, day or night; it can be used to identify stars or planets, to determine local latitude given local time (and vice versa), to survey, or to triangulate. It was used in classical antiquity, the Islamic Golden Age, the European Middle Ages and the Age of Discovery for all these purposes.

The astrolabe’s importance comes not only from the early developments into the study of astronomy,^[1] but is also effective for determining latitude on land or calm seas. Although it is less reliable on the heaving deck of a ship in rough seas, the mariner’s astrolabe was developed to solve that problem.

Examples of astrolabes

A spherical astrolabe from medieval Islamic astronomy, c. 1480, most likely Syria or Egypt, in the Museum of the History of Science, Oxford[2]	An astrolabe from the Mamluk Sultanate dated 1282.
The Canterbury Astrolabe Quadrant, England, 1388.	A 16th-century astrolabe showing a tulip rete and rule.

Applications

A 10th Century astronomer deduced that there were around 1000 applications for the astrolabe’s various functions,^{[3][better source needed]} and these ranged from the astrological, the astronomical and the religious, to seasonal and daily time-keeping and tide tables. At the time of their use, astrology was widely considered as much of a serious science as astronomy, and study of the two went hand-in-hand. The astronomical interest varied between folk astronomy (of the pre-Islamic tradition in Arabia) which was concerned with celestial and seasonal observations, and mathematical astronomy, which would inform intellectual practices and precise calculations based on astronomical observations. In regards to the astrolabe’s religious functionality, the demands of Islamic prayer times were to be astronomically determined to ensure precise daily timings, and the qibla, the direction of Mecca towards which Muslims must pray, could also be determined by this device. In addition to this, the lunar calendar that was informed by the calculations of the astrolabe was of great significance to the religion of Islam, given that it determines the dates of important religious observances such as Ramadan.

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Etymology

OED gives the translation “star-taker” for the English word astrolabe and traces it through medieval Latin to the Greek word astrolabos,^[4][5] from astron “star” and lambanein “to take“.^[6] In the medieval Islamic world the Arabic word al-Asturlāb (i.e. astrolabe) was given various etymologies. In Arabic texts, the word is translated as ākhidhu al-Nujūm (Arabic: آخِذُ ٱلنُّجُومْ‎, lit. “star-taker”), a direct translation of the Greek word.^[7]

Al-Biruni quotes and criticises medieval scientist Hamzah al-Isfahani who stated:^[7] “asturlab is an arabisation of this Persian phrase” (sitara yab, meaning “taker of the stars”).^[8] In medieval Islamic sources, there is also a folk etymology of the word as “lines of lab“, where “Lab” refers to a certain son of Idris (Enoch). This etymology is mentioned by a 10th-century scientist named al-Qummi but rejected by al-Khwarizmi.^[9]

Idrīs, in Islam, prophet mentioned in the Qurʾān (Islamic sacred scriptures) as an immortal figure. According to tradition, Idrīs appeared sometime between the prophets Adam and Noah and transmitted divine revelation through several books. He did not die but was taken bodily to paradise to spend eternity with God. Popular legend also credits him with the invention of writing, sewing, and several forms of divination. He is regarded as the patron saint of craftsmen and Muslim knights. (Well, he is clearly not ENOCH from the Bible  This is a fallen angel, who taught mankind all the arts and crafts, which are not from God.  NO servant of God would teach DIVINATION!  You can see below any connection made to Enoch is just a figment of imagination.  They connect this being to all kinds of historical figures, including Hermes.) Little is said about Idrīs in the Qurʾān. Later Islamic tradition often identifies him with Enoch, a biblical patriarch who is also said to have been taken physically to paradise. Connections have also been made to Elijah or al-Khiḍr, another vague Qurʾānic figure whom later tradition elaborated as immortal. On linguistic grounds scholars outside the Islamic tradition have variously identified him as the biblical Ezra, the Christian Apostle Andrew, and Andreas, the cook for Alexander the Great in Alexander romance literature. Muslim folk traditions have also woven Hermes Trismegistos, a legendary figure in Hermetism, into the popular personage of Idrīs.

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History

Ancient world

An early astrolabe was invented in the Hellenistic civilization by Apollonius of Perga between 220 and 150 BC, often attributed to Hipparchus. The astrolabe was a marriage of the planisphere and dioptra, effectively an analog calculator capable of working out several different kinds of problems in astronomy. Theon of Alexandria (c. 335 – c. 405) wrote a detailed treatise on the astrolabe, and Lewis^[10] argues that Ptolemy used an astrolabe to make the astronomical observations recorded in the Tetrabiblos.

Astrolabes continued in use in the Greek-speaking world throughout the Byzantine period. About 550 AD, Christian philosopher John Philoponus wrote a treatise on the astrolabe in Greek, which is the earliest extant treatise on the instrument.^[a] Mesopotamian bishop Severus Sebokht also wrote a treatise on the astrolabe in the Syriac language in the mid-7th century.^[b] Sebokht refers to the astrolabe as being made of brass in the introduction of his treatise, indicating that metal astrolabes were known in the Christian East well before they were developed in the Islamic world or in the Latin West.^[15]

Medieval era

Astrolabes were further developed in the medieval Islamic world, where Muslim astronomers introduced angular scales to the design,^[16] adding circles indicating azimuths on the horizon.^[17] It was widely used throughout the Muslim world, chiefly as an aid to navigation and as a way of finding the Qibla, the direction of Mecca. Eighth-century  mathematician  Muhammad al-Fazari is the first person credited with building the astrolabe in the Islamic world.^[18]

The mathematical background was established by Muslim astronomer Albatenius in his treatise Kitab az-Zij (c. 920 AD), which was translated into Latin by Plato Tiburtinus (De Motu Stellarum). The earliest surviving astrolabe is dated AH 315 (927–28 AD).^[19] In the Islamic world, astrolabes were used to find the times of sunrise and the rising of fixed stars, to help schedule morning prayers (salat). In the 10th century, al-Sufi first described over 1,000 different uses of an astrolabe, in areas as diverse as astronomy, astrology, navigation, surveying, timekeeping, prayer, Salat, Qibla, etc.^[20][21]

The spherical astrolabe was a variation of both the astrolabe and the armillary sphere, invented during the Middle Ages by astronomers and inventors in the Islamic world.^[c] The earliest description of the spherical astrolabe dates back to Al-Nayrizi (fl. 892–902). In the 12th century, Sharaf al-Dīn al-Tūsī invented the linear astrolabe, sometimes called the “staff of al-Tusi”, which was “a simple wooden rod with graduated markings but without sights. It was furnished with a plumb line and a double chord for making angular measurements and bore a perforated pointer”.^[22] The geared mechanical astrolabe was invented by Abi Bakr of Isfahan in 1235.^[23]

The first known metal astrolabe in Western Europe is the Destombes astrolabe made from brass in the eleventh century in Portugal.^[24][25] Metal astrolabes avoided the warping that large wooden ones were prone to, allowing the construction of larger and therefore more accurate instruments. Metal astrolabes were heavier than wooden instruments of the same size, making it difficult to use them in navigation.^[26]

Herman Contractus of Reichenau Abbey, examined the use of the astrolabe in Mensura Astrolai during the 11th century.^[27] Peter of Maricourt wrote a treatise on the construction and use of a universal astrolabe in the last half of the 13th century entitled Nova compositio astrolabii particularis. Universal astrolabes can be found at the History of Science Museum in Oxford.^[28] David A. King, historian of Islamic instrumentation, describes the universal astrolobe designed by Ibn al-Sarraj of Aleppo (aka Ahmad bin Abi Bakr; fl. 1328) as “the most sophisticated astronomical instrument from the entire Medieval and Renaissance periods”.^[29]

English author Geoffrey Chaucer (c. 1343–1400) compiled A Treatise on the Astrolabe for his son, mainly based on a work by Messahalla or Ibn al-Saffar.^[30][31] The same source was translated by French astronomer and astrologer Pélerin de Prusse and others. The first printed book on the astrolabe was Composition and Use of Astrolabe by Christian of Prachatice, also using Messahalla, but relatively original.

In 1370, the first Indian treatise on the astrolabe was written by the Jain astronomer Mahendra Suri, titled Yantrarāja.^[32]

A simplified astrolabe, known as a balesilha, was used by sailors to get an accurate reading of latitude while out to sea. The use of the balesilha was promoted by Prince Henry (1394–1460) while out navigating for Portugal.^[33]

The astrolabe was almost certainly first brought north of the Pyrenees by Gerbert of Aurillac (future Pope Sylvester II), where it was integrated into the quadrivium at the school in Reims, France sometime before the turn of the 11th century.^[34] In the 15th century, French instrument maker Jean Fusoris (c. 1365–1436) also started remaking and selling astrolabes in his shop in Paris, along with portable sundials and other popular scientific devices of the day. Thirteen of his astrolabes survive to this day.^[35] One more special example of craftsmanship in early 15th-century Europe is the astrolabe designed by Antonius de Pacento and made by Dominicus de Lanzano, dated 1420.^[36]

In the 16th century, Johannes Stöffler published Elucidatio fabricae ususque astrolabii, a manual of the construction and use of the astrolabe. Four identical 16th-century astrolabes made by Georg Hartmann provide some of the earliest evidence for batch production by division of labor.

Quadrivium From the time of Plato through the Middle Ages, the quadrivium (plural: quadrivia[1]) was a grouping of four subjects or arts—arithmetic, geometry, music, and astronomy—that formed a second curricular stage following preparatory work in the trivium, consisting of grammar, logic, and rhetoric. Together, the trivium and the quadrivium comprised the seven liberal arts,[2] and formed the basis of a liberal arts education in Western society until gradually displaced as a curricular structure by the studia humanitatis and its later offshoots, beginning with Petrarch in the 14th century. The seven classical arts were considered “thinking skills” and were distinguished from practical arts, such as medicine and architecture. The quadrivium, Latin for ‘four ways‘,[3] and its use for the four subjects have been attributed to Boethius, who likely coined the term.[4] It was considered the foundation for the study of philosophy (sometimes called the “liberal art par excellence“)[5] and theology. The quadrivium was the upper division of the medieval education in the liberal arts, which comprised arithmetic (number in the abstract), geometry (number in space), music (number in time), and astronomy (number in space and time). These four studies compose the secondary part of the curriculum outlined by Plato in The Republic and are described in the seventh book of that work (in the order Arithmetic, Geometry, Astronomy, Music).[2] The quadrivium is implicit in early Pythagorean writings and in the De nuptiis of Martianus Capella, although the term quadrivium was not used until Boethius, early in the sixth century.[10] As Proclus wrote: The Pythagoreans considered all mathematical science to be divided into four parts: one half they marked off as concerned with quantity, the other half with magnitude; and each of these they posited as twofold. A quantity can be considered in regard to its character by itself or in its relation to another quantity, magnitudes as either stationary or in motion. Arithmetic studies quantities as such, music the relations between quantities, geometry magnitude at rest, spherics [astronomy] magnitude inherently moving.[1

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Ingenious Clocks from Muslim Civilisation that Defied the Middle Ages

TIME TELLING MACHINES: Revealing marvellous mechanical and water-powered clocks from early Muslim Civilisation. These sophisticated devices that defied the Middle Ages.

Figure 1. Elephant Clock in Ibn Battuta Mall, Dubai
Note: Composed by Cem Nizamoglu and first published in 1001 Inventions website.

Clocks and timekeeping were one of the most significant developments of Muslim civilisation. Scholars, inventors and craftsmen made innovative automata, carried out detailed mathematical analysis, constructed intricate clocks and attempted to master automatic control as they created and expanded upon inventions to mark and measure time.

The Arabs [and non-Arabs from Muslim Civilisation] also made better and more accurate devices for measuring time, clepsydras or water-clocks. The earliest reference to a clock is found in al-Jahiz’s Kitab-al-Hayawan in the second half of the 9th centurys.” George Sarton*

*Introduction to the History of Science Vol.11 Part II by George Sarton, Baltimore, William and Wilkins company, 1931, p.632.

Our kings and scientists use the astrolabe by day and the binkamat (water-clocks) by night” Al-Jahiz, Kitab-al-Hayawan

This may be the earliest record of clocks in Muslim Civilisation history. However, the quote itself shows that the usage of clocks was a common practice in and before 9th Century– maybe even the making of clocks. Clock-makers from Muslim Civilisation indeed, used Indian and Greek technology. Though Archimedes book on the water-clocks was not just preserved in Arabic – advancement and the creativity in building clocks became a form of art like the astrolabes. This also contributed towards the development in automata and other technological advancements.  .

Figure 2. The internal workings of a water-clock. From ‘The Book of Archimedes on the Construction of Water-Clocks’ in Arabic. Or. 14270, f. 16v (Source)

As in the west so in the east, but here we have far more information. In the hands of Arab scholars [and non-Arabs from Muslim Civilisation] not only was the Greek tradition of water clocks developed, but detailed descriptions were written by the compilers of The Book of Archimedes on the Construction of Water-Clocks (eighth to twelfth centuries); by al-Muradi (eleventh century); al-Khazini (early twelfth century); Ridwan (late twelfth to early thirteenth century); and al-Jazarl (late twelfth to early thirteenth century).”*

*Encyclopedia of Time by Samuel L. Macey, Routledge, 2013, Page 310

‘Stand the test of time’ clocks have been used in Muslim Civilisation from the early ages of Islam. ‘Time is of the essence’ clocks turned from a development in technology to an art form. Huge clocks, sometimes reaching 6 meters high, were designed by the likes of Al-Jazari and others. ‘In time’ towers, mosques and even whole streets turned in to clocks, for example with the construction of clocks such as the Bou’Anania clock (see figures 22-24) . ‘As time goes by’ not just in automata, robotics or other technologies, clock development competed with astrolabe development in astronomy in example Taqi al-Din’s Astronomical clock (see figures 7-8). ‘There was a time when’ sending clocks as gifts became a policy between nations; it even reached from Ottomans to Mexicans (see figures 38). ‘Once upon a time’ in Europe, a figure on a clock of the ‘French Charles X in Ottoman outfit riding an Arab stallion’ (see figure 25), demonstrating how clocks even became a fashion statement (see figures 35-36). Most importantly, clocks were a shared legacy, especially clocks from Muslim Civilisation were “ahead of their time”. One only needs to observe how Archimedes works were preserved in Arabic (see above figure 2) or how Al-Jazari’s “Elephant clock” embodied Indian, Persian, Greek, Egyptian, Chinese and Arabic elements almost as if it was an united nations’ clock (see figures 15-16) . ‘Only time will tell’ but to take one nation’s contribution out would be taking one gear out from a clock… hopefully you will find much more information and examples in Professor Al-Hassani’s upcoming book on clocks; ‘all in good time’…

Here are some key examples:

1. Al-Jazari’s Castle Clock, 12th century

Figures 3-4. Manuscript view of the castle clock (Left) and computer assisted reconstruction (Right) © 1001 Inventions

The first machine described by Al-Jazari in his famous treatise of mechanics Al-Jami‘ bayn al-‘ilm wa ‘l-‘amal al-nafi‘ fi sina‘at al-hiyal (‘A Compendium on the Theory and Useful Practice of the Mechanical Arts’) is a monumental water clock known as the Castle Clock.

The castle water clock is one of the grandest clocks mentioned in Al-Jazari’s book. Details of its construction and operation are described in ten sections of the first chapter of Category I of the treatise.

The clock, with its series of mechanical routines that ran throughout the day, would have been very pleasing to watch and listen to. During daylight hours, an observer would have seen the Sun’s disc on the eastern horizon about to rise, the Moon would not be seen at all and six zodiac signs would be visible, while the first point of the constellation Libra was about to set.

The crescent Moon would travel steadily from left to right on the frieze. When between two doors, the upper door would open to reveal a figure of a man, while the lower door flipped round to reveal a different colour. This occured as each solar hour of sunlight has passed. Soon after this happens, the two falcons would tilt forward and spread their wings, and a ball would drop out of their beaks and into the vase. The observer would hear a cymbal-like sound, and both falcons would lean back to their original position and close their wings…

Muslim Heritage: Al-Jazari’s Castle Water Clock by Salim Al-Hassani

It is impossible to over-emphasize the importance of al-Jazari’s work in the history of engineering. Until modern times there is no other document from any cultural area that provides a comparable wealth of instructions for the design, manufacture and assembly of machines… Al-Jazari did not only assimilate the techniques of his non-Arab and Arab predecessors, he was also creative. He added several mechanical and hydraulic devices. The impact of these inventions can be seen in the later designing of steam engines and internal combustion engines, paving the way for automatic control and other modern machinery. The impact of al-Jazari’s inventions is still felt in modern contemporary mechanical engineering…” Donald R. Hill

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2. The Ummayad Clock, 13th century

Figure 5. Dome of the clocks in the courtyard of the of Umayyad Mosque in Damascus. © Bernard Gagnon (31 March 2010)

Originally built in the famous Umayyad mosque in Damacus more than 800 years ago, this clock was re-constructed by Ridhwan al-Sa’ati. This impressive mechanical clock displayed the time numerically and included two falcons that would automatically throw a copper ball into a vase to mark the passing of an hour. At night, a lamp would be lit to indicate the hour by shining through a turning disc.

Figure 6.The general plan of the Umayyad mosque water clock as drafted by Ridhwan al-Sa’ati in his original manuscript.

According to descriptions by Ibn Jubayr, geographer, traveler and poet from al-Andalus (Muslim Spain), the clock had both an upper level and a lower section.

The lower section housed the engine that generated the movements and transmitted them by ropes and pulleys to the upper part. The engine worked by means of a float in a water tank (bankan). Upon draining the water from the tank, through an orifice at the bottom, the float moved down under the force of gravity, pulling a rope over a pulley which caused the movement of all the other parts. The float movement was controlled by the speed with which the water surface moved down in itself regulated by a control valve attached to the orifice.

Muslim Heritage: From Frankfurt and Cairo to Damascus by Abdel Aziz Al-Jaraki

In 1154. Arab engineer al-Kaysarani constructed the world’s first striking clock. near the Umayyad mosque in Damascus. It was powered by water and was described by at-Kaysarani’s son Ridwan al Sa’ati in his 1203 treatise On the Construction of Clocks and their Use. Islamic water clocks became so sophisticated that in 1235 one was built in Baghdad that told people the times of prayer, day and night.” DK*

*Science Year by Year by Dorling Kindersley (DK) Ltd, 2013, Page 57

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3. Taqi al-Din’s Clock, 16th century

Figures 7-8. In the middle part of this famous manuscrtipt of an Istanbul observatory (left) is a clock placed on a table that is believed to be Taqi al-Din’s. Computer animated rendering of the workings of Taqī al-Dīn’s observational clock is shown on the right.  © 1001 Inventions

In his book ‘The Brightest Stars for the Construction of Mechanical Clocks’ (Al-Kawakib al-durriyya fi wadh’ al-bankamat al-dawriyya), Taqi al-Din Ibn Ma’ruf analyses the four main types of time keeping devices known in the 16th century: watches, domestic clocks, astronomical clocks and tower clocks. Such machines represent the earliest mechanical computers.

Before the 16th century, clocks were considered too inaccurate for measuring celestial movements. Where Ptolemy failed to succeed in, Taqī al-Dīn planned to build an astronomical clock that would measure time with great regularity in fulfillment of the wish of the Sultan at the time.

Using mathematics, he designed three dials which showed the hours, degrees and minutes. In his clock, he incorporated the use of several escapements, an alarm, the striking trains that sounded at every hour, the visual relationship between the sun and the moon, the different phases of the moon, the devices that indicated the time for prayers and the dials that showed the first day of the Gregorian months.

Taqī al-Dīn’s work on mechanical clocks is of important significance in light of transmission of knowledge between cultures and advancement of technology within the Middle East in the middle of the 16th century. Many of the devices mentioned in his clock are present in today’s clocks from all around the world.

Muslim Heritage: The Astronomical Clock of Taqi Al-Din by Salim Al-Hassani

Regarded as the greatest scientist and engineer of the Ottoman Empire, and one of the last of the great Islamic polymaths, Taqi al-Din made significant contributions to areas as diverse as optics, horology, hydraulics, and steam power. He wrote more than 90books on a wide variety of subjects, ranging from astronomy and natural philosophy to engineering, clocks, mathematics, and mechanics, which contain detailed descriptions and discussions of his work. Many of these treatises were translated into European languages and reached the West.”  Adam Hart-Davis*

*Engineers by Adam Hart-Davis, Dorling Kindersley Ltd, 2012, Page 56

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4. Al-Muradi’s Clock, The Book of Secrets, 11th century

Figures 9-10. Al-Muradi describing the solar clock in his “Book of Secrets” (on the left), 3D computer animated image of solar clock (on the right)

Some of the earliest descriptions in Arabic of water clocks are available in Al-Muradi’s ‘The Book of Secrets’, there has been found some of the earliest descriptions in Arabic of water clocks. This book deals with water clocks and other devices that use automata. The treatise consists of 31 models of which fiveare essentially very large toys similar to clocks, in that automata are caused to move at intervals, but without precise timing.

There are nineteen clocks all of which record the passage of the temporal hours by the movements of automata. The power came from flowing water, and it was transmitted to automata by very sophisticated mechanisms, which included gears and the use of mercury. These are highly significant features; they provide the first known examples of complex gearing used to transmit high torque, while the adoption of mercury reappears in European clocks from the thirteenth century onwards.

Unfortunately, the only known manuscript of this work is badly defaced and it is not possible to understand exactly how the clocks worked. A weight-driven clock with a mercury escapement appears in “Libros del Saber”, a work written in Spanish at the court of Alfonso of Castille in about 1277and consisting of translations and paraphrases of Arabic works. A novel feature in this treatise is the use of mercury in balances. Al-Zarquali built two large water clocks on the banks of the river Tagus at Toledo in 11th century.

Muslim Heritage: A Review of Early Muslim Control Engineering by Mohamed Mansour

When I looked at the science of engineering and saw that it had disappeared after its ancient heritage,that its masters have perished, and that their memories are now forgotten, I worked my wits and thoughts in secrecy about philosophical shapes and figures, which could move the mind, with effort, from nothingness to being and from idleness to motion. And I arranged these shapes one by one in drawings and explained them.” Al-Muradi*

*“Kitab al-Asrar fi Nataij al-Afkar” (Book of Secrets) by Al-Muradi, source: www.leonardo3.net

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5. The Al-Qarawiyyin Clock, 13th century

Figures 11-12. Photo (Right) of the Al-Lija’i clepsydra clock located in the room of al-Muwaqqit (timekeeper) in the minaret of the Al-Qarawiyyin mosque (Left) in Fes, Morocco. © 1001 Inventions

Amongst the most remarkable historical objects in the Maghrib are the clocks in Fez in Morocco. One of these, a water clock operated by levers and strings and without any complicated gear mechanisms, was located in a room in the minaret of the Qarawiyyin Mosque. It was made in 1286/87by Ibn al-Habbak al-Tilimsani, and when it was restored in 1346-48by Abu Abdallah al-‘Arabi it was fitted with an astrolabic rete to help track the stars. Alas, the driving mechanism behind the clock is lost without trace, and it is not clear what changes have been made to the front of the clock. But fortunately, the astrolabic part survives to this day. It is housed in a cabinet 2.4 meters high and 1.2 meters square; the rete is about 40 cm in diameter and would have rotated once every 24 hours. It thus could imitate the apparent daily rotation of the heavens about the horizon of Fez, a kind of model of the universe in two dimensions. In addition, metal balls would fall through the doors above the clock every hour.

The muwaqqit was the officer charged with the regulation and maintenance of the clocks and with communicating the correct times of prayer to the muezzin who would lead the call to prayer. The most important object of the Dar al-Muwaqqit is the water clock of Al-Lija’i made at the order of the Marinid Sultan Abu Salim Ali II (r. 1359-1361) by Abu Zaid Abdurrahman Ibn Suleyman al-Lija’i (d. 1370). Notice the 12 doors under and above the disk; the red wooden structure is the top part of the clock. Source: La clepsydre Al-Lijai.

Muslim Heritage: History, Culture, and Science in Morocco by Salah Zaimeche

The tradition of building monumental water-clocks continued in Islam after the time of al-Jazari, as is proved by the remains of two large constructions dating to the 8th/14th century in Fez, Morocco.’ The first of these, at the Bu`ananiyya Mosque… The second clock is located in the upper room in the minaret of the Qarawiyyin University Mosque. It was built in 736/1362 by Abu `Abd Allah Muhammad al-Arabi, on the site of two earlier clocks.It is fitted with an astrolabic rete and an elegant fixed dial, the rate being carried on a wooden axle projected into the interior chamber. This is, therefore, a similar device to the anaphoric clock described by Vitruvius…”  Donald R Hill*

*Sources & Studies in the History of Arabic-Islamic Science History of Technology, Series – 4 – Arabic Water-Clocks by Donald R Hill, University of Aleppo, 1981, Page 123

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6. Ibn al-Haytham’s Mechanical Water Clock 10th century

Figures 13-14. 3D animation images of the reconstructed model of Ibn al-Haytham’s clock.  © 1001 Inventions

Better known for his ground-breaking discoveries in optics,Ibn al-Haytham’s work on the water clock (Maqala fi ‘amal al-binkam) is also very significant.

In his writings, Ibn al-Haytham gives details of the water clock. He describes it as a new invention in that it gives hours and minutes, which no other clock had previously shown. He refers to making and manufacturing the clock, as well as testing it by trial and error.

The time-measuring mechanism he used was a cylinder with a small hole at its base as the prime mover for telling the time. As the cylinder sank downwards into another tank, which contained a sufficient amount of water, it resembled an inflow clepsydra, measuring time by the amount of water that had flowed in. This was unlike the clepsydras used in antiquity, which were later adapted by Muslim engineers Al-Muradi, Ibn Ridhwan al-Sa’ati and Al-Jazari. These were all outflow clepsydras, measuring time by the amount of water that had flown out. It is interesting that Ibn al-Haytham should use inflow technology for the control of his clock instead of the outflow clepsydra, which should have been well known in Cairo at the time when he was in Egypt.

Muslim Heritage: The Mechanical Water Clock Of Ibn Al-Haytham  by Salim Al-Hassani

In the ninth century, an elaborate water-clock was presented to Charlemagne by vassals of Harun al-Rashid, an indication that these devices were made in early Abbasid times. In his Book of the Balance of Wisdom, written about AD 1121, al-Khazini refers to various water-clocks built by his predecessors, in particular the great Egyptian scientist Ibn al-Haytham (965-1039).” Donald R Hill*

* A History of Engineering in Classical and Medieval Times by Donald R Hill, Routledge, 2013, Page 232

www.IbnAlhaytham.com

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7. Al-Jazari’s Elephant Clock, 13th century

Figures 15-16. Elephant Clock manuscript by Al-Jazari from The Book of Knowledge of Ingenious Mechanical Devices (Left) A reproduction of the elephant clock in the Ibn Battuta Mall, Dubai (Right)

Al-Jazari’s 800-year-old automatic Elephant Clockis probably the most famous of clocks from Muslim civilisation.

The large clock uses Greek water-raising technology, an Indian elephant, an Egyptian phoenix, Arabian figures and Chinese dragons, to celebrate the diversity of the world.

Muslim Heritage: Overview on al-Jazari and his Mechanical Devices by Yavuz Unat

The Holy Qur’an encourages Muslims to seek knowledge throughout their lives, no matter what the source or where it might lead geographically. Islamic civilizations have celebrated and worked towards cross-boundary knowledge sharing. Al-Jazari, for example, once built an elaborate clock, the Elephant Clock, in order to celebrate the diversity of mankind and the universal nature of Islam. It depicted different Greek, Indian, Phoenician, Chinese and Persian artifacts on the clock as, by that time, the Muslim world had spread from Spain to Central Asia.” Caroline Ellwood*

*Learning and Teaching about Islam: Essays in Understanding by Caroline Ellwood, John Catt Educational Ltd, 2012, Page 31

A short film on Al-Jazari’s Elephant Clock below:

***

Appendix

According to Al-Djazairi* there are “Flawed Claims Relating to Technological Breakthroughs” and one of this claims was related to clocks:

…the claim that there had been no technological advances between Antiquity and the ‘Renaissance is expressed by Bedini:

There appears to be no longer any question, on the basis of recent research, that the mechanical clock and fine instrumentation evolved in a direct line without substantial change from the mechanical water clocks of the Alexandrian civilisation, transmitted through Islam and Byzantines.”
Silvio A Bedini*

*The Role of Automata in the History of Technology; in Technology and Culture Vol 5 by S A Bedini pp 24-42; at p. 29.

This is a misconceived view (although shared by many.) It first of all contradicts the view of medievalist historians who, correctly, give the Middle Ages a leading place in technological breakthroughs, including the development of mechanical clocks and fine instruments. Moreover, as Hill, most certainly the scholar giving most attention to technology from Muslim Civilisation, notes, fine technology is a recognizable Muslim profession, and if any modern engineer:

Might refer to Greek works, he could find most of his inspiration in the works of his Muslim predecessors.A similar process that can be observed with other sciences and technologies.”
Donald R. Hill*

*Engineering in the Encyclopaedia by Donald R. Hill (Rashed ed), op cit, pp. 751-95; at p. 786.

This can easily be verified by comparing both traditions, the Greek and the Muslim to realise, indeed, that the latter bears the strongest affinities with modern technology, with respect to every single device. A valuable recent article by Aiken on the impact of Al-Jazari (fl. 1206) goes a long way to prove this point. The ingenious complexity of his devices, as well as his desire to instruct followers in the art and scienceof making them, Aiken points out, compelled al-Jazari to provide more detailed written descriptions of their inner workings than those found in any known older treatise. The instructive value of al-Jazari’s innovative drawings are obvious when compared to the typically more abbreviated illustrations found in a 13th century copy of Hero of Alexandria’s Pneumatica of the first century. As one might expect not only does Hero hardly mention the manufacturing process in the text of his treatise, he never explains how to construct any part of the machine, no matter how critical. By contrast, al-Jazari’s text and illustrations represent the growing importance and status of mechanical arts in the Middle Ages as well as their association with the most sweeping kinds of earthly, philosophical, and cosmological order.

Perhaps, [Aiken says] most important from the point of view of understanding more about the perceptual and intellectual context of Renaissance perspective and of medieval technical drawings, al-Jazari’s illustrations express a fundamental need for the visual communication of useful information about material reality in an age when pictures are most closely associated with the aspatial, the iconic, and the other-worldly.”Jane Andrews Aiken*

*Truth in images from the technical drawings of al-Jazari by J A Aiken, Campanus of Novara, 1994; pp. 325-359; at p. 344.

*From “The Hidden Debt to Islamic Civilisation, Volume II” by Al-Djazairi, S.E..

Further Reading

• Muslim Heritage: The Clock of Civilisations
• eduardfarre.com: The Clepsydra of the Gazelles by Eduard Farré i Olivé 
• Harun Al-Rashid’s Clock to Charlemagne:

“In the second passage from Rev. Kenner Davenport’s The Reasonable Horologist, he reflects on man’s early attempts to capture time more precisely.  Clepsydra refers to a water clock (its Greek translation is “water thief”) which measures time by regulating the flow of liquid from one vessel to another.

In 807, Emperor Charlemagne was sent a brass clock by the Abbasid caliph, Harun al-Rashid in Baghdad.  According to the Emperor’s biographer, it was a “marvellous mechanical contraption, in which the course of the twelve hours moved according to a water clock, with as many brazen little balls, which fell down on the hourand through their fall made a cymbal ring underneath. On this clock there were also twelve horsemen who at the end of each hour stepped out of twelve windows, closing the previously open windows by their movements.”  bookdrum.com: Charlemagne’s Elephant by Richard Hodges (Figure 17. Imaginary image of the scene, on the right)

• saudiaramcoworld.com: An Elephant for Charlemagne by Jon Mandaville
• Muslim Heritage: Ridhwan al-Sa’ati: A Biographical Outline by Moustafa Mawaldi
• qdl.qa: Robots, Musicians and Monsters: The World’s Most Fantastic Clocks by Bink Hallum
• muslimheritage.com/clocks

Fig18. Left side of the clock Lund Cathedral Clock

“While in the cathedral, I walked over to the medieval astronomical clock to await the moving figures and music that accompany the striking of the hour. During my wait, I noticed four carved figures that had been placed in each of the corners of the top part of the clock. The figures were wearing exotic clothing and one even wore a turban, immediately bringing to mind the image of an Arabic astronomer. This challenged my previous assumption that Muslims had generally been portrayed in a negative light in medieval Scandinavia. Indeed, it actually seemed to suggest that there was a sense of pride in having these figures here occupying a prominent place within the walls of one of medieval Scandinavia‟s most important ecclesiastical buildings. This encounter tied in with research that I had been undertaking on the influence and dissemination of Arabic ‪‎scientific‬ works in Scandinavia, particularly in ‪Iceland‬…” Dr Christian Etheridge

Fig 19. Right side of the clock Lund Cathedral Clock

Figure 26. Reconstruction of the clock of Al-Muradi by Spanish scholars. A general view with its side opening revealing the working of the mechanism. Source: Eduard Farré Olivé , De Mensura Temporis. (1ª parte) “Arte y Hora” n. 123-H6, March-April 1997, pp. 8-16 (2ª parte) “Arte y Hora” n. 127-H10, January-February 1998, pp. 10-17; and Eduard Farré Olivé, La clepsidra de las Gacelas del manuscrito de relojes de Al-Muradi.

Figure 27. Al-Jazari’s Elaphant Clock done by children (Source)	Figure 28. Similar to Al-Jazari’s Elaphant Clock “Water clock of the boat”

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Figure 30. Al-Jazari and “The Book of Knowledge of Ingenious Mechanical Devices” from BBC’s Dick and Dom’s “Absolute Genius” (Source)

Figure 31. Professor Salim al-Hassani with Dick and Dom in the Bodleian Library, looking at the one of the rare copies of Al-Jazari’s clock Manuscript, University of Oxford (Source)

 
Figure 33. Al-Biruni’s Mechanical Calendar (British Library, MS OR 5593).

Figure 37. Queen Elizabeth I (Thomas Dallam’s Organ) clock gift to Ottoman Sultan Mehmet III 1599 (Source)

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HOME › HANDS-ON › HANDS-ON WITH SEIKO’S (NEW) QUARTZ ASTRON

Hands-on with Seiko’s (new) Quartz Astron

BY HOROLOGIUM on NOVEMBER 2, 2010 • ( 0 )

December 2009 was the 40th anniversary of the world’s first Quartz wristwatch, the Seiko Quartz Astron 35SQ. Based on a quartz crystal oscillator (an electrical signal with an extremely precise frequency), its importance is acknowledged by its registration on the IEEE Milestone list as a major advance in electrical engineering.

Seiko marked this anniversary by the commissioning of 40 new watch designs all based around the original Quartz Astron design, which were exhibited in the ‘Seiko Power Design Project’ in Dec 2009.

The culmination of Seiko’s commemoration was the new Quartz Astron, powered by the SEIKO quartz caliber 9F62, accurate within 10 seconds a year, and with its date change completed in an astonishing 1/2,000 of a second.

HISTORY

Project 59A

In 1880 Pierre and Jacques Curie discovered the electrical potential of quartz crystals when pressure is applied, known as piezoelectricity. They devised the piezoelectric quartz electrometer, which can measure faint electric currents. The question was then how to practically apply this.

By 1927 Bell Laboratories demonstrated that accurate time could be measured by using a quartz crystal and implementing the results of the Curie brother’s experiments. In 1959 Suwa Seikosha Co Ltd, one of Seiko Group’s Research and Development labs, built its first quartz timepiece, a large clock 2 meters high and 1.5 meters wide, which was successfully used in a radio station in Japan. The task was then given of miniaturising this new technology, and Project 59A was launched.

In 1962, the company managed to produce ‘smaller’ (30kg) version of a quartz marine chronometer, which was utilised in the Japanese shipping industry. By 1963, Seiko managed to further miniaturise it down to the 3kg QC0951.

Launched at Basel in 1969, the original Quartz Astron was produced in 18 carat gold case in a run of 100 pieces costing JPY 450,000, more than a Toyota Corolla at the time.

The first quartz watch that was available to the general public was the 3823 calibre, also known as the 38 SQW, which was introduced in October 1971 at a price of JPY 150,000. This was equivalent to two month’s salary for a Japanese university lecturer.

SEIKO Quartz Astron : The Commemorative Edition

TECHNICAL SPECIFICATIONS

Reference: S23617J1
Calibre: 9F62
Dimensions: 26.75 mm (12 – 6 o’clock) x 26.0 mm (3 – 9 o’clock)
Depth: 3.1 mm (without battery)
Jewels: 9
Accuracy: +/- 10 seconds per year
Battery life: 3 years (battery life indicator)
Case: High-intensity titanium
Band: Silicone with stainless steel buckle
Extra band: Crocodile with black hard-coated stainless steel three-fold clasp with push button release
Glass: Curved sapphire crystal with anti-reflective coating
Water resistance: 10 bar
Magnetic resistance: 4,800 A/m (60 gauss)
Functions : hour, minute and second hands, date with instant calendar change mechanism
Battery life indicator
Limited edition of 200

This brings me to the price of this watch :

RRP Europe: Euro 4,300
RRP U.S. : USD 5,000
RRP Australia : AUD 8,500

[Addendum (5/10/2019) – on the occasion of the 50th anniversary, Seiko have released the 1969 Quartz Astron 50th Anniversary limited edition.]

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Meet the watch that shook up Switzerland

Commemorate an engineering milestone with the Timemaster Piezo Watch.

It was the watch that changed everything. In the history of timepieces, few moments are more important than the creation of the world’s first Piezo quartz timepiece. First released to the public in 1969, the watch turned the entire industry on its head, inaugurating a new era of timekeeping. It’s this legacy that we’re honoring with theTimemaster Piezo Watch, available only through Stauer.

Prior to Piezo watches, gravity-driven Swiss watches were the standard bearer of precision

You are here: Home page > Electricity and electronics > Piezoelectricity

Piezoelectricity

by Chris Woodford. Last updated: December 11, 2020.

You’ve probably used piezoelectricity (pronounced “pee-ay-zo-electricity”) quite a few times today. If you’ve got a quartz watch, piezoelectricity is what helps it keep regular time. If you’ve been writing a letter or an essay on your computer with the help of voice recognition software, the microphone you spoke into probably used piezoelectricity to turn the sound energy in your voice into electrical signals your computer could interpret. If you’re a bit of an audiophile and like listening to music on vinyl, your gramophone would have been using piezoelectricity to “read” the sounds from your LP records. Piezoelectricity (literally, “pressing electricity”) is much simpler than it sounds: it just means using crystals to convert mechanical energy into electricity or vice-versa. Let’s take a closer look at how it works and why it’s so useful!

Photo: A piezoelectric actuator used by NASA for various kinds of testing. Photo by courtesy of NASA Langley Research Center (NASA-LaRC).

What is piezoelectricity?

Squeeze certain crystals (such as quartz) and you can make electricity flow through them. The reverse is usually true as well: if you pass electricity through the same crystals, they “squeeze themselves” by vibrating back and forth. That’s pretty much piezoelectricity in a nutshell but, for the sake of science, let’s have a formal definition:

Piezoelectricity (also called the piezoelectric effect) is the appearance of an electrical potential (a voltage, in other words) across the sides of a crystal when you subject it to mechanical stress (by squeezing it).

In practice, the crystal becomes a kind of tiny battery with a positive charge on one face and a negative charge on the opposite face; current flows if we connect the two faces together to make a circuit. In the reverse piezoelectric effect, a crystal becomes mechanically stressed (deformed in shape) when a voltage is applied across its opposite faces.

What causes piezoelectricity?

Think of a crystal and you probably picture balls (atoms) mounted on bars (the bonds that hold them together), a bit like a climbing frame. Now, by crystals, scientists don’t necessarily mean intriguing bits of rock you find in gift shops: a crystal is the scientific name for any solid whose atoms or molecules are arranged in a very orderly way based on endless repetitions of the same basic atomic building block (called the unit cell). So a lump of iron is just as much of a crystal as a piece of quartz. In a crystal, what we have is actually less like a climbing frame (which doesn’t necessarily have an orderly, repeating structure) and more like three-dimensional, patterned wallpaper.

Artwork: What scientists mean by a crystal: the regular, repeating arrangement of atoms in a solid. The atoms are essentially fixed in place but can vibrate slightly.

In most crystals (such as metals), the unit cell (the basic repeating unit) is symmetrical; in piezoelectric crystals, it isn’t. Normally, piezoelectric crystals are electrically neutral: the atoms inside them may not be symmetrically arranged, but their electrical charges are perfectly balanced: a positive charge in one place cancels out a negative charge nearby. However, if you squeeze or stretch a piezoelectric crystal, you deform the structure, pushing some of the atoms closer together or further apart, upsetting the balance of positive and negative, and causing net electrical charges to appear. This effect carries through the whole structure so net positive and negative charges appear on opposite, outer faces of the crystal.

The reverse-piezoelectric effect occurs in the opposite way. Put a voltage across a piezoelectric crystal and you’re subjecting the atoms inside it to “electrical pressure.” They have to move to rebalance themselves—and that’s what causes piezoelectric crystals to deform (slightly change shape) when you put a voltage across them.

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What is piezoelectricity used for?

Photo: A typical piezoelectric transducer. This one is the ringer inside my landline telephone: it makes a particularly shrill and horrible chirping noise when the phone rings!

There are all kinds of situations where we need to convert mechanical energy (pressure or movement of some kind) into electrical signals or vice-versa. Often we can do that with a piezoelectric transducer. A transducer is simply a device that converts small amounts of energy from one kind into another (for example, converting light, sound, or mechanical pressure into electrical signals).

In ultrasound equipment, a piezoelectric transducer converts electrical energy into extremely rapid mechanical vibrations—so fast, in fact, that it makes sounds, but ones too high-pitched for our ears to hear. These ultrasound vibrations can be used for scanning, cleaning, and all kinds of other things.

In a microphone, we need to convert sound energy (waves of pressure traveling through the air) into electrical energy—and that’s something piezoelectric crystals can help us with. Simply stick the vibrating part of the microphone to a crystal and, as pressure waves from your voice arrive, they’ll make the crystal move back and forth, generating corresponding electrical signals. The “needle” in a gramophone (sometimes called a record player) works in the opposite way. As the diamond-tipped needle rides along the spiral groove in your LP, it bumps up and down. These vibrations push and pull on a lightweight piezoelectric crystal, producing electrical signals that your stereo then converts back into audible sounds.

Photo: Record-player stylus (photographed from underneath): If you’re still playing LP records, you’ll use a stylus like this to convert the mechanical bumps on the record into sounds you can hear. The stylus (silver horizontal bar) contains a tiny diamond crystal (the little dot on the end at the right) that bounces up and down in the record groove. The vibrations distort a piezoelectric crystal inside the yellow cartridge that produces electrical signals, which are amplified to make the sounds you can hear.

In a quartz clock or watch, the reverse-piezoelectric effect is used to keep time very precisely. Electrical energy from a battery is fed into a crystal to make it oscillate thousands of times a second. The watch then uses an electronic circuit to turn that into slower, once-per-second beats that a tiny motor and some precision gears use to drive the second, minute, and hour hands around the clock-face.

Piezoelectricity is also used, much more crudely, in spark lighters for gas stoves and barbecues. Press a lighter switch and you’ll hear a clicking sound and see sparks appear. What you’re doing, when you press the switch, is squeezing a piezoelectric crystal, generating a voltage, and making a spark fly across a small gap.

If you’ve got an inkjet printer sitting on your desk, it’s using precision “syringes” to squirt droplets of ink onto the paper. Some inkjets squirt their syringes using electronically controlled piezoelectric crystals, which squeeze their “plungers” in and out; Canon Bubble Jets fire their ink by heating it instead. (You’ll find more details of both methods in our article about inkjet printers.)

Photo: NASA has experimented with using piezoelectric materials to reduce the vibration and noise from rapidly spinning helicopter rotors. Photo courtesy of NASA.

Energy harvesting with piezoelectricity?

If you can make a tiny bit of electricity by pressing one piezoelectric crystal once, could you make a significant amount by pressing many crystals over and over again? What if we buried crystals under city streets and pavements to capture energy as cars and people passed by? This idea, which is known as energy harvesting, has caught many people’s interest. Inventors have proposed all kinds of ideas for storing energy with hidden piezoelectric devices, from shoes that convert your walking movements into heat to keep your feet warm, and cellphones that charge themselves from your body movements, to roads that power streetlights, contact lenses that capture energy when you blink, and even gadgets that make energy from the pressure of falling rain.

Artwork: Energy harvesting? Inventors have been filing lots of patents for wearable gadgets that will generate small amounts of electricity from your body movements. This example is a shoe with a built-in piezoelectric transducer (1) that springs up and down as you walk, sending electricity to a circuit (2) and then storing it in a battery (3).

Is energy harvesting a good idea? At first sight, anything that minimizes waste energy and improves efficiency sounds really sensible. If you could use the floor of a grocery store to capture energy from the feet of hurrying shoppers pushing their heavy carts, and use that to power the store’s lights or its chiller cabinets, surely that must be a good thing? Sometimes energy harvesting can indeed provide a decent, if rather modest, amount of power.

The trouble is, however, that energy harvesting schemes can be a big distraction from better ideas. Consider, for example, the concept of building streets with piezoelectric “rumble strips” that soak up energy from passing traffic. Cars are extremely inefficient machines and only a small amount (15 percent or so) of the energy in their fuel powers you down the road. Only a fraction of this fraction is available for recovery from the road—and you wouldn’t be able to recover all that fraction with 100 percent efficiency. So the amount of energy you could practically recover, and the efficiency gain you would make for the money you spent, would be minuscule. If you really want to save energy from cars, the sensible way to do it is to address the inefficiencies of car transportation much earlier in the process; for example, by designing engines that are more efficient, encouraging people to car share, swapping from gasoline engines to electric cars, and things of that sort.

That’s not to say that energy harvesting has no place; it could be really useful for charging mobile devices using energy that would otherwise go to waste. Imagine a cellphone that charged itself automatically every time it jiggled around in your pocket, for example. Even so, when it comes to saving energy, we should always consider the bigger picture and make sure the time and money we invest is producing the best possible results.

Who discovered piezoelectricity?

The piezoelectric effect was discovered in 1880 by two French physicists, brothers Pierre and Paul-Jacques Curie, in crystals of quartz, tourmaline, and Rochelle salt (potassium sodium tartrate). They took the name from the Greek work piezein, which means “to press.” Jacques summed up the observation in an 1889 paper in Annales de Chimie et de Physique (my own very rough translation from the French):

“If one pulls or squeezes along the main axis [of a quartz block], there appears at the ends of this axis equal quantities of electricity of opposite signs, proportional to the acting force and independent of the dimensions of the quartz.“

Artwork: Illustrations of the Curies’ work from Quartz Piezo-Electrique: Extrait de la These de J. CURIE: Annales de Chimie et de Physique, t. XVII, 1889, p. 392.
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Epson – Wikipedia

The company has developed many timepiece technologies. In particular, it developed the world’s first portable quartz timer (Seiko QC-951) in 1963, the world’s first quartz watch (Seiko Quartz Astron 35SQ) in 1969, the first automatic power generating quartz watch (Seiko Auto-Quartz) in 1988 and the Spring Drive watch movement in 1999.

Harvesting Vibrations with Piezoelectrics | DigiKey

https://www.digikey.com/en/articles/harvesting-vibrations-with-piezoelectrics

One of the first applications of the piezoelectric effect was in the detectors of sonar instruments for locating submarines (1917). Seiko released the first quartz watch in 1969. Electronic drum kits use piezoelectric elements to sense the strength of a strike and send an equivalent electrical signal to a speaker.

What is the magic of piezoelectricity?

The magic of piezoelectricity owes its existence to a quantum effect.  Just take as an example the piezoelectric compound “lead titanate”  PbTiO3. If you stretch your mind down to the level of the simplest atomic structure that can exhibit the piezoelectric effect, it’s a box made of atoms. At the corners of the box are 8 “anchor” lead (Pb)  atoms. Near the center of each of the six faces of that box are 6 oxygen (O) atoms.  These 14 atoms make a cage, and it completely traps one single titanium (Ti) atom. In the fuzzy world of quantum mechanics, that titanium atom can lodge in only one of several stable energy states inside the cage, each of which is associated with a “position” (fuzzy) within the box. Here’s the nut: even though the titanium can’t escape, when it does settle in any one of its quantum “positions,”  the whole cage shape warps mechanically to accommodate it. The cage remains charge neutral, but it has an internal dipole electric field that balances the titanium position offset.

When the cage sees an electric field (externally applied voltage), the balance is altered, and the frame of the box shifts slightly (shrinks/expands). When the frame of the box is mechanically stressed (by pressure), it distorts and the Ti atom position shifts (charge “flow”).

The geometry of the crystal and its electrical state are inextricably coupled.

You might imagine that as the temperature of a piezoelectric transducer goes down to absolute zero ( 0 degrees Kelvin), that its magic gets frozen just like everything else.  But the magic remains. It’s based on electric field effects, and electric fields do not disappear EVEN at absolute zero. Generally the macroscopic properties of piezoceramics do shift as the temperature drops. Motion per volt and volts per motion change to be sure, but they don’t disappear.

For more on the magic of piezoelectricity, download Rob’s free PDF resource HERE

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Clepsydra

timekeeping device

Alternate titles: water clock

Key People:

Ctesibius Of Alexandria

Related Topics:

time Clock Machine

Clepsydra, also called water clock, ancient device for measuring time by the gradual flow of water. One form, used by the North American Indians and some African peoples, consisted of a small boat or floating vessel that shipped water through a hole until it sank. In another form, the vessel was filled with water that was allowed to escape through a hole, and the time was read from graduated lines on the interior measuring the level of the remaining water. It may have been an invention of the Chaldeans of ancient Babylonia; specimens from Egypt date from the 14th century BC. The Romans invented a clepsydra consisting of a cylinder into which water dripped from a reservoir; a float provided readings against a scale on the cylinder wall. Clepsydras were used for many purposes, including timing the speeches of orators; as late as the 16th century, Galileo used a mercury clepsydra to time his experimental falling bodies.

Pythagoreanism

The earliest known systematic cult based on the rule of numbers was that of the Pythagoreans. Pythagoras was a Greek who thrived in the 6th century BCE. Little is known of his life, and in fact he may be a composite figure to whom the discoveries of many different people have been attributed by his followers. It is not even known whether the Pythagorean theorem in geometry was actually discovered by him.

The Pythagoreans invested specific numbers with mystical properties. The number 1 symbolized unity and the origin of all things, since all other numbers can be created from 1 by adding enough copies of it. For example, 7 = 1 + 1 + 1 + 1 + 1 + 1 + 1. The number 2 was symbolic of the female principle, 3 of the male; they come together in 2 + 3 = 5 as marriage. All even numbers were female, all odd numbers male. The number 4 represented justice. The most perfect number was 10, because 10 = 1 + 2 + 3 + 4. This number symbolized unity arising from multiplicity. Moreover, it was related to space. A single point corresponds to 1, a line to 2 (because a line has two extremities), a triangle to 3, and space to 4. Thus 10 also symbolized all possible spaces.

The Pythagoreans recognized the existence of nine heavenly bodies: Sun, Moon, Mercury, Venus, Earth, Mars, Jupiter, Saturn, and the so-called Central Fire. So important was the number 10 in their view of cosmology that they believed there was a tenth body, Counter-Earth, perpetually hidden from us by the Sun.

Some Pythagorean speculations were mathematical. They represented numbers by arrangements of dots. The square numbers (1, 4, 9, 16,…) were arranged in squares, and the triangular numbers (1, 3, 6, 10,…) were arranged in triangles (see figure). This terminology remains in use to the present day.

The Pythagoreans were especially fascinated by the presence of numbers in the natural world. Perhaps their most spectacular discovery was that musical harmony is related to simple whole-number ratios. A string (such as that on a violin) produces a note with a particular pitch; a string one-half as long produces an extremely harmonious note to the first, now called the octave. A string two-thirds as long produces the next most harmonious note, now called the fifth. And one three-fourths as long produces the fourth, also very harmonious. The Pythagoreans discovered these facts empirically by experimenting with strings of different lengths. Today these harmonies are traced to the physics of vibrating strings, which move in patterns of waves. The number of waves that can fit into a given length of string is a whole number, and these whole numbers determine the simple numerical ratios. When the numbers do not form a simple ratio, the corresponding notes interfere with each other and form discordant “beats” that are unpleasant to the ear. The full story is more complex, involving what the brain becomes accustomed to, but there is a definite rationale behind the Pythagorean discovery. This later led the German astronomer Johannes Kepler to the concept of the “music of the spheres,” a kind of heavenly harmony in which the planets effectively produced tunes as they moved across the heavens. Some of Kepler’s theories about the planets, such as the elliptical shape of their orbits, became solid science—but not this one. Nonetheless, it was influential in establishing the view that there is some kind of order in the cosmos, an idea that culminated in Isaac Newton’s law of gravity.

Galileo

Italian philosopher, astronomer and mathematician

Alternate titles: Galileo Galilei

BY Albert Van Helden | View Edit History

FAST FACTS

Facts & Related Content Timeline Achievements

Galileo

Born: February 15, 1564 Pisa Italy

Died: January 8, 1642 (aged 77) Italy

Inventions: Galilean telescope hydrostatic balance thermometer compass

Notable Works: “Dialogue Concerning the Two Chief World Systems—Ptolemaic and Copernican” “The Sidereal Messenger”

Notable Family Members: father Vincenzo Galilei

Galileo, in full Galileo Galilei, (born February 15, 1564, Pisa [Italy]—died January 8, 1642, Arcetri, near Florence), Italian natural philosopher, astronomer, and mathematicianwho made fundamental contributions to the sciences of motion, astronomy, and strength of materialsand to the development of thescientific method. His formulation of (circular) inertia, the law of falling bodies, and parabolic trajectories marked the beginning of a fundamental change in the study of motion. His insistence that the book of nature was written in the language of mathematics changed natural philosophy from a verbal, qualitative account to a mathematical one in which experimentation  became a recognized method for discovering the facts of nature. Finally, his discoveries with the telescope  revolutionized astronomy and paved the way for the acceptance of the Copernican  heliocentric system, but his advocacy of that system eventually resulted in an Inquisition process against him.

Early life and career

Galileo was born in Pisa, Tuscany, on February 15, 1564, the oldest son of Vincenzo Galilei, a musician who made important contributions to the theory and practice of music  and who may have performed some experiments with Galileo in 1588–89 on the relationship between pitch and the tension of strings. The family moved to Florence in the early 1570s, where the Galilei family had lived for generations. In his middle teens Galileo attended the monastery school at Vallombrosa, near Florence, and then in 1581 matriculated at the University of Pisa, where he was to study medicine. However, he became enamoured with mathematics  and decided to make the mathematical subjects and philosophy his profession, against the protests of his father. Galileo then began to prepare himself to teach  Aristotelian philosophyand mathematics, and several of his lectures have survived. In 1585 Galileo left the university without having obtained a degree, and for several years he gave private lessons in the mathematical subjects in Florence and Siena. During this period he designed a new form of hydrostatic balance for weighing small quantities and wrote a short treatise, La bilancetta (“The Little Balance”), that circulated in manuscript form. He also began his studies on motion, which he pursued steadily for the next two decades.

In 1588 Galileo applied for the chair of mathematics at the University of Bologna but was unsuccessful. His reputation was, however, increasing, and later that year he was asked to deliver two lectures to the Florentine Academy, a prestigious literary group, on the arrangement of the world in Dante’sInferno. He also found some ingenious theorems on centres of gravity(again, circulated in manuscript) that brought him recognition among mathematicians and the patronage of Guidobaldo del Monte (1545–1607), a nobleman and author of several important works on mechanics. As a result, he obtained the chair of mathematics at the University of Pisa in 1589.There, according to his first biographer, Vincenzo Viviani (1622–1703), Galileo demonstrated, by dropping bodies of different weights from the top of the famous Leaning Tower, that the speed of fall of a heavy object is not proportional to its weight, as Aristotle had claimed. The manuscript tract De motu (On Motion), finished during this period, shows that Galileo was abandoning Aristotelian notions about motion and was instead taking an Archimedean approach to the problem. But his attacks on Aristotle made him unpopular with his colleagues, and in 1592 his contract was not renewed. His patrons, however, secured him the chair of mathematics at the University of Padua, where he taught from 1592 until 1610.

Archimedes, (born c. 287 BCE, Syracuse, Sicily [Italy]—died 212/211 BCE, Syracuse), the most famous mathematician and inventor in ancient Greece. Archimedes is especially important for his discovery of the relation between the surface and volume of a sphere and its circumscribing cylinder. He is known for his formulation of a hydrostatic principle (known as Archimedes’ principle) and a device for raising water, still used, known as the Archimedes screw.

His life

Archimedes probably spent some time in Egyptearly in his career, but he resided for most of his life in Syracuse, the principal Greek city-state in Sicily, where he was on intimate terms with its king, Hieron II. Archimedes published his works in the form of correspondence with the principal mathematicians of his time, including the Alexandrian scholars Conon of Samos and Eratosthenes of Cyrene.

he is credited with inventing the Archimedes screw, and he is supposed to have made two “spheres” that Marcellus took back to Rome—one a star globe and the other a device (the details of which are uncertain) for mechanically representing the motions of the Sun, the Moon, and the planets. The story that he determined the proportion of gold and silver in a wreath made for Hieron by weighing it in water is probably true, but the version that has him leaping from the bath in which he supposedly got the idea and running naked through the streets shouting “Heurēka!” (“I have found it!”) is popular embellishment. Equally apocryphal are the stories that he used a huge array of mirrors to burn the Roman ships besieging Syracuse; that he said, “Give me a place to stand and I will move the Earth”; and that a Roman soldier killed him because he refused to leave his mathematical diagrams—although all are popular reflections of his real interest in catoptrics(the branch of optics dealing with the reflection of light from mirrors, plane or curved),mechanics, and pure mathematics.

his interest in mechanics deeply influenced his mathematical thinking. Not only did he write works on theoretical mechanics and hydrostatics, but his treatise Method Concerning Mechanical Theorems shows that he used mechanical reasoning as a heuristic device for the discovery of new mathematical theorems.

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Isaac Newton, in full Sir Isaac Newton, (born December 25, 1642 [January 4, 1643, New Style], Woolsthorpe, Lincolnshire, England—died March 20 [March 31], 1727, London), English physicist and mathematician, who was the culminating figure of the Scientific Revolution of the 17th century. In optics, his discovery of the composition of white light integrated the phenomena of colours into the science of light and laid the foundation for modern physical optics. In mechanics, his three laws of motion, the basic principles of modern physics, resulted in the formulation of the law of universal gravitation. In mathematics, he was the original discoverer of the infinitesimal calculus. Newton’sPhilosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy, 1687) was one of the most important single works in the history of modern science.

Born in the hamlet of Woolsthorpe, Newton was the only son of a local yeoman, also Isaac Newton, who had died three months before, and of Hannah Ayscough. That same year, at Arcetri near Florence, Galileo Galilei had died; Newton would eventually pick up his idea of a mathematical science of motion and bring his work to full fruition. A tiny and weak baby, Newton was not expected to survive his first day of life, much less 84 years. Deprived of a father before birth, he soon lost his mother as well, for within two years she married a second time; her husband, the well-to-do minister Barnabas Smith, left young Isaac with his grandmother and moved to a neighbouring village to raise a son and two daughters. For nine years, until the death of Barnabas Smith in 1653, Isaac was effectively separated from his mother, and his pronounced psychotic tendencies have been ascribed to this traumatic event. That he hated his stepfather we may be sure. When he examined the state of his soul in 1662 and compiled a catalog of sins in shorthand, he remembered “Threatning my father and mother Smith to burne them and the house over them.” The acute sense of insecurity that rendered him obsessively anxious when his work was published and irrationally violent when he defended it accompanied Newton throughout his life and can plausibly be traced to his early years.

Newton was sent back to the grammar school in Grantham, where he had already studied, to prepare for the university. As with many of the leading scientists of the age, he left behind in Grantham anecdotes about his mechanical ability and his skill in building models of machines, such as clocks and windmills. At the school he apparently gained a firm command of Latin but probably received no more than a smattering of arithmetic. By June 1661 he was ready to matriculate at Trinity College, Cambridge, somewhat older than the other undergraduates because of his interrupted education.

When Newton arrived in Cambridge in 1661, the movement now known as the Scientific Revolution was well advanced, and many of the works basic to modern science had appeared. Astronomers fromNicolaus Copernicus to Johannes Keplerhad elaborated the heliocentric systemof theuniverse. Galileo had proposed the foundations of a new mechanicsbuilt on the principle of inertia. Led by René Descartes, philosophers had begun to formulate a new conception of nature as an intricate, impersonal, and inert machine. Yet as far as the universities of Europe, including Cambridge, were concerned, all this might well have never happened. They continued to be the strongholds of outmoded Aristotelianism, which rested on a geocentric view of the universe and dealt with nature in qualitative rather than quantitative terms.

Newton discovered the works of the French natural philosopher Descartes and the other mechanical philosophers, who, in contrast to Aristotle, viewed physical reality as composed entirely of particles of matter in motionand who held that all the phenomena of nature result from their mechanical interaction

Newton had discovered the new conception of nature that provided the framework of the Scientific Revolution. He had thoroughly mastered the works of Descartes and had also discovered that the French philosopher Pierre Gassendi had revived atomism, an alternativemechanical system to explain nature. The “Quaestiones” also reveal that Newton already was inclined to find the latter a more attractive philosophy than Cartesian natural philosophy, which rejected the existence of ultimate indivisible particles.

Significantly, he had read Henry More, the Cambridge Platonist, and was thereby introduced to another intellectual world, the magical Hermetictradition,which sought to explain natural phenomena in terms of alchemical and magical concepts

Newton had also begun his mathematical studies. He again started with Descartes, from whose La Géometrie he branched out into the other literature of modern analysis with its application of algebraic techniques to problems of geometry. He then reached back for the support of classical geometry. Within little more than a year, he had mastered the literature; and,pursuing his own line of analysis, he began to move into new territory. He discovered the binomial theorem, and he developed the calculus,a more powerful form of analysis that employs infinitesimal considerations in finding the slopes of curves and areas under curves.

During the plague years Newton laid the foundations of the calculus and extended an earlier insight into an essay, “Of Colours,” which contains most of the ideas elaborated in his Opticks. It was during this time that he examined the elements of circular motion and, applying his analysis to the Moon and the planets, derived the inverse square relation that the radially directed force acting on a planet decreases with the square of its distance from the Sun—which was later crucial to the law of universal gravitation.

(1670–72), his lectures developed the essay “Of Colours” into a form which was later revised to become Book One of his Opticks.

Beginning with Kepler’s Paralipomena in 1604, the study of optics had been a central activity of the Scientific Revolution. Descartes’s statement of the sine law of refraction, relating the angles of incidence and emergence at interfaces of the media through which light passes, had added a new mathematical regularity to the science of light, supporting the conviction that the universe is constructed according to mathematical regularities

Newton fully accepted the mechanical nature of light, although he chose the atomistic alternative and held that light consists of material corpuscles in motion. The corpuscular conception of light was always a speculative theory on the periphery of his optics, however. The core of Newton’s contribution had to do with colours. An ancient theory extending back at least to Aristotle held that a certain class of colour phenomena, such as the rainbow,arises from the modification of light, which appears white in its pristine form. Descartes had generalized this theory for all colours and translated it into mechanical imagery. Through a series of experiments performed in 1665 and 1666, in which the spectrum of a narrow beam was projected onto the wall of a darkened chamber, Newton denied the concept of modification and replaced it with that of analysis.

Basically, he denied that light is simple and homogeneous—stating instead that it is complex and heterogeneous and that the phenomena of colours arise from the analysis of the heterogeneous mixture into its simple components. The ultimate source of Newton’s conviction that light is corpuscular was his recognition that individual rays of light have immutable properties; in his view, such properties imply immutable particles of matter. He held that individual rays (that is, particles of given size) excite sensations of individual colours when they strike the retina of the eye. He also concluded that rays refract at distinct angles—hence, the prismatic spectrum, a beam of heterogeneous rays, i.e., alike incident on one face of a prism, separated or analyzed by the refraction into its component parts—and that phenomena such as the rainbow are produced by refractive analysis. Because he believed thatchromatic aberration could never be eliminated from lenses, Newton turned to reflecting telescopes; he constructed the first ever built. The heterogeneity of light has been the foundation of physical optics since his time.

the theory of colours, like his later work, was transmitted to the world through the Royal Society of London, which had been organized in 1660. When Newton was appointed Lucasian professor, his name was probably unknown in the Royal Society; in 1671, however, they heard of his reflecting telescope and asked to see it. Pleased by their enthusiastic reception of the telescope and by his election to the society, Newton volunteered a paper on light and colours early in 1672.

a second paper, an examination of the colour phenomena in thin films, which was identical to most of Book Two as it later appeared in the Opticks. The purpose of the paper was to explain the colours of solid bodies by showing how light can be analyzed into its components by reflection as well as refraction.His explanation of the colours of bodies has not survived, but the paper was significant in demonstrating for the first time the existence of periodic optical phenomena. He discovered the concentric coloured rings in the thin film of air between a lens and a flat sheet of glass; the distance between these concentric rings (Newton’s rings) depends on the increasing thickness of the film of air. In 1704 Newton combined a revision of his optical lectures with the paper of 1675 and a small amount of additional material in his Opticks.

Newton was also engaged in another exchange on his theory of colours with a circle of EnglishJesuits in Liège, perhaps the most revealing exchange of all. Although their objections were shallow, their contention that his experiments were mistaken lashed him into a fury. The correspondence dragged on until 1678, when a final shriek of rage from Newton, apparently accompanied by a complete nervous breakdown, was followed by silence. The death of his mother the following year completed his isolation.

Influence of the Hermetic tradition

During his time of isolation, Newton was greatly influenced by the Hermetic tradition with which he had been familiar since his undergraduate days. Newton, always somewhat interested in alchemy, now immersed himself in it, copying by hand treatise after treatise and collating them to interpret their arcane imagery. Under the influence of the Hermetic tradition, his conception of nature underwent a decisive change. Until that time, Newton had been a mechanical philosopher in the standard 17th-century style, explaining natural phenomena by the motions of particles of matter. Thus, he held that the physical reality of light is a stream of tiny corpuscles diverted from its course by the presence of denser or rarer media. He felt that the apparent attraction of tiny bits of paper to a piece of glass that has been rubbed with cloth results from an ethereal effluvium that streams out of the glass and carries the bits of paper back with it. This mechanical philosophy denied the possibility of action at a distance; as with static electricity, it explained apparent attractions away by means of invisible ethereal mechanisms. Newton’s “Hypothesis of Light” of 1675, with its universal ether, was a standard mechanical system of nature. Some phenomena, such as the capacity of chemicals to react only with certain others, puzzled him, however, and he spoke of a “secret principle” by which substances are “sociable” or “unsociable” with others. About 1679, Newton abandoned the ether and its invisible mechanisms and began to ascribe the puzzling phenomena—chemical affinities, the generation of heat in chemical reactions, surface tension in fluids, capillary action, the cohesion of bodies, and the like—to attractions and repulsions between particles of matter. More than 35 years later, in the second English edition of the Opticks, Newton accepted an ether again, although it was an ether that embodied the concept of action at a distance by positing a repulsion between its particles. The attractions and repulsions of Newton’s speculations were direct transpositions of the occult sympathies and antipathies of Hermetic philosophy—as mechanical philosophers never ceased to protest. Newton, however, regarded them as a modification of the mechanical philosophy that rendered it subject to exact mathematical treatment. As he conceived of them, attractions were quantitatively defined, and they offered a bridge to unite the two basic themes of 17th-century science—the mechanical tradition, which had dealt primarily with verbal mechanical imagery, and the Pythagoreantradition, which insisted on the mathematical nature of reality. Newton’s reconciliation through the concept offorce was his ultimate contribution to science.

Pythagoreanism (1) the metaphysic of number and the conception that reality, including music and astronomy, is, at its deepest level, mathematical in nature; (2) the use ofphilosophyas a means of spiritual purification; (3) the heavenly destiny of the soul and the possibility of its rising to union with the divine; (4) the appeal to certain symbols, sometimes mystical, such as the tetraktys, the golden section, and the harmonyof the spheres; (5) the Pythagorean theorem; and (6) the demand that members of the order shall observe a strict loyalty and secrecy. Pythagorean theorem, the well-known geometric theorem that the sum of the squares on the legs of a right triangle is equal to the square on the hypotenuse (the side opposite the right angle)—or, in familiar algebraic notation, a2 + b2 = c2. Pythagoreanism was akin to trends seen in mystery religions and emotional movements, such as Orphism, which often claimed to achieve through intoxication a spiritual insight into the divine origin and nature of the soul. Yet there are also aspects of it that appear to have owed much to the more sober, “Homeric” philosophy of the Ionians. The Pythagoreans, for example, displayed an interest in metaphysics, as did their naturalistic predecessors, though they claimed to find its key in mathematical form rather than in any substance. They accepted the essentially Ionian doctrines that the world is composed of opposites (wet-dry, hot-cold, and so on) and generated from something unlimited; but they added the idea of the imposition of limit upon the unlimited and the sense of a musical harmony in the universe.Again, like the Ionians, they devoted themselves to astronomical and geometrical speculation. Combining, as it does, a rationalistic theory of number with a mystic numerology and a speculative cosmology with a theory of the deeper, more enigmatic reaches of the soul, Pythagoreanism interweaves rationalism and irrationalismmore inseparably than does any other movement in ancient Greek thought. The belief in the transmigration of souls provided a basis for the Pythagorean way of life. Some Pythagoreans deduced from this belief the principle of “the kinship of all beings,” the ethical implications of which were later stressed in 4th-century speculation. Pythagoras himself seems to have claimed a semidivine status in close association with the superior godApollo; he believed that he was able to remember his earlier incarnations and, hence, to know more than others knew. Research in the 20th century emphasized shamanistic traits deriving from the ecstatic cult practices of Thracianmedicine men in the early Pythagorean outlook. The rules for the religious life that Pythagoras taught were largely ritualistic: refrain from speaking about the holy, wear white clothes, observe sexual purity, do not touch beans, and so forth. He seems also to have taught purification of the soul by means of music and mental activity (later called philosophy)in order to reach higher incarnations. “To be like your Master” and so “to come nearer to the gods” was the challenge that he imposed on his pupils. Salvation, and perhaps ultimate union with the divine cosmos through the study of the cosmic order, became one of the leading ideas in his school. The harmony of the cosmos The sacred decad (the sum of the first four numbers) in particular has a cosmic significance in Pythagoreanism: its mystical name, tetraktys  (meaning approximately “fourness”), implies 1 + 2 + 3 + 4 = 10; but it can also be thought of as a “perfect triangle.” Speculation on number and proportion led to an intuitive feeling of the  harmonia  (“fitting together”) of the kosmos (“order of things”); and the application of the tetraktys to the theory of music (see below Music) revealed a hidden order in the range of sound. Pythagorasmay have referred, vaguely, to the “music of the heavens,” which he alone seemed able to hear; and later Pythagoreans seem to have assumed that the distances of the heavenly bodies from the earth somehow correspond to musical intervals—a theory that, under the influence of Platonic conceptions, resulted in the famous idea of the “harmony of the spheres.”

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How Isaac Newton Changed the World with the Invention of Calculus

Released – March 18, 2017

Isaac Newton changed the world when he invented Calculus in 1665. We take this for granted today, but what Newton accomplished at the age of 24 is simply astonishing.

What Is Calculus?

At its most basic, calculus is all about studying the rate of change of a quantity over time. In particular, it can be narrowed down to the study of the rate of change and summation of quantities. The two categories of calculus are called differential calculus and integral calculus.  Differential calculus deals with the rate of change of a quantity such as how the position of an object changes compared to time. Integral calculus is all about accumulation, or summing up infinitely small quantities. The fundamental theorem of calculus is what connects these two categories. This theorem guarantees the existence of antiderivatives for continuous functions.

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