Louise of Mecklenburg-Strelitz

Louise of Mecklenburg-Strelitz (Luise Auguste Wilhelmine Amalie; 10 March 1776 – 19 July 1810) was Queen of Prussia as the wife of King Frederick William III. The couple's happy, though short-lived, marriage produced nine children, including the future monarchs Frederick William IV of Prussia and Wilhelm I, German Emperor.

Her legacy became cemented after her extraordinary 1807 meeting with French Emperor Napoleon I at Tilsit – she met with the emperor to plead unsuccessfully for favorable terms after Prussia's disastrous losses in the Napoleonic Wars. She was already well loved by her subjects, but her meeting with Napoleon led Louise to become revered as "the soul of national virtue". Her early death at the age of thirty-four "preserved her youth in the memory of posterity", and caused Napoleon to reportedly remark that the king "has lost his best minister". The Order of Louise was founded by her grieving husband four years later as a female counterpart to the Iron Cross. In the 1920s, conservative German women founded the Queen Louise League.

## Duchess of Mecklenburg-Strelitz (1776–1793)

Duchess Luise Auguste Wilhelmine Amalie of Mecklenburg-Strelitz ("Louise" in English) was born on 10 March 1776 in a one-storey villa, just outside the capital in Hanover. She was the fourth daughter and sixth child of Duke Charles of Mecklenburg and his wife Princess Friederike of Hesse-Darmstadt. Her father Charles was a brother of Queen Charlotte and her mother Frederike was a granddaughter of Louis VIII, Landgrave of Hesse-Darmstadt. Her maternal grandmother, Landgravine Marie Louise of Hesse-Darmstadt, and her paternal first-cousin Princess Augusta Sophia of the United Kingdom served as sponsors at her baptism; her second given name came from Princess Augusta Sophia.

At the time of her birth, Louise's father was not yet the ruler of Mecklenburg-Strelitz (he would not succeed his brother as Duke until 1794), and consequently she was not born in a court, but rather in a less formal home. Charles was field marshal of the household brigade in Hanover, and soon after Louise's birth he was made Governor-General of that territory by his brother-in-law George III, king of the United Kingdom and Hanover (husband of his sister, Queen Charlotte). The family subsequently moved to Leineschloss, the residence of Hanoverian kings, though during the summer they usually lived at Herrenhausen.

Louise was particularly close to her sister Frederica, who was two years younger, as well as with their only brother George. Louise and her siblings were under the care of their governess Fräulein von Wolzogen, a friend of their mother's. When Louise was only six years old, her mother died in childbirth, leaving a permanent mark on the young duchess; she would often give away pocket change to other children who experienced similar losses, stating "she is like me, she has no mother". After Duchess Friederike's death, the family left Leineschloss for Herrenhausen, sometimes called a "miniature Versailles". Duke Charles remarried two years later to his first wife's younger sister Charlotte, producing a son, Charles. Louise and her new stepmother became close until Charlotte's early death the year after their marriage. The twice widowed and grieving duke went to Darmstadt, where he gave the children into the care of his mother-in-law and Louise's grandmother, the widowed Landgravine Marie Louise.

### Education

Their grandmother preferred to raise them simply, and they made their own clothes. A new governess from Switzerland, Madame Gelieux, was appointed, giving the children lessons in French; as was common for royal and aristocratic children of the time, Louise became fluent and literate in the language, while neglecting her own native German. She received religious instruction from a clergyman of the Lutheran Church. Complementary to her lessons was an emphasis on charitable acts, and Louise would often accompany her governess when visiting the houses of the poor and needy. Louise was encouraged to give out as much as was in her means, although she often got into trouble with her grandmother for donating too much for charity. From the age of ten until her marriage at 17, Louise spent most of her time in the presence of her grandmother and governess, both well-educated and refined. When only nine years old, Louise was present when the poet Friedrich Schiller read from the first act of "Don Carlos" for the entertainment of the assembled court, thus sparking her love for German as a literary language, especially works of Schiller. Louise loved history and poetry, and not only enjoyed reading Schiller, but also came to like the works of Goethe, Paul, Herder and Shakespeare, as well as ancient Greek tragedies.

In 1793, Marie Louise took the two youngest duchesses with her to Frankfurt, where she paid her respects to her nephew King Frederick William II. Louise had grown up into a beautiful young woman, possessing "an exquisite complexion" and "large blue eyes," and was naturally graceful. Louise's uncle, the Duke of Mecklenburg, hoped to strengthen ties between his house and Prussia. Consequently, on one evening carefully planned by the Duke, seventeen-year-old Louise met the king's son and heir, Crown Prince Frederick William. The crown prince was twenty-three, serious-minded, and religious. She made such a charming impression on Frederick William that he immediately made his choice, desiring to marry her. Frederica caught the eye of his younger brother Prince Louis Charles, and the two families began planning a double betrothal, celebrating a month later, on 24 April 1793 in Darmstadt. Frederick and Louise were subsequently married on 24 December that same year, with Louis and Frederica marrying two days later.

## Crown Princess of Prussia (1793–1797)

In the events leading up to her marriage, Louise's arrival in Berlin, the Prussian capital, caused quite a sensation, and she was greeted with a grand reception by the city's joyful citizens. When she broke protocol and stopped to pick up and kiss a child, Prussian writer Friedrich de la Motte Fouqué remarked that "The arrival of the angelic Princess spreads over these days a noble splendor. All hearts go out to meet her, and her grace and goodness leaves no one unblessed." Another wrote "The more perfectly one becomes acquainted with the Princess the more one is captivated by the inner nobility, and the angelic goodness of her heart."

Louise's father-in-law King Frederick William II gave the couple Charlottenburg Palace, but the crown prince and his new wife preferred to live at Paretz Palace, just outside Potsdam, where Louise kept herself busy with household affairs. Paretz was far from the bustle of court, as the couple were most content in the "rural retirement" of a country life. The marriage was happy, and Louise was well-beloved by the king, who called her "the princess of princesses" and gave her a palace in Oranienburg. The crown princess saw it as her duty to support her husband in all his pursuits, and the couple enjoyed singing together and reading from Shakespeare and Goethe. Louise soon became pregnant, giving birth to a stillborn girl on 1 October 1794 at the age of eighteen. Nine healthy children would follow in quick succession, though two died in childhood: Crown Prince Frederick William (1795), Prince William (1797), Princess Charlotte (1798), Princess Frederica (1799), Prince Charles (1801), Princess Alexandrine (1803), Prince Ferdinand (1804), Princess Louise (1808), and Prince Albert (1809). The couple also used the Crown Prince's Palace in the capital.

Louise's charitable giving continued throughout her life, and on one occasion, while attending a harvest festival, she purchased presents and distributed them to local children. On her first birthday after her marriage in Berlin, when King Frederick William II asked his daughter-in-law what she desired for a present, Louise replied she wanted a handful of money to let the city's people share her joy; he smilingly gave her a large quantity for the task.

## Queen consort of Prussia (1797–1810)

On 16 November 1797, her husband succeeded to the throne of Prussia as King Frederick William III after the death of his father. Louise wrote to her grandmother, "I am now queen, and what rejoices me most is the hope that now I need no longer count my benefactions so carefully." The couple had to abandon their solitude at Paretz and begin living under the restraints of a royal court. They began a tour of the country's eastern provinces for two purposes: the king wanted to acquaint himself with their new subjects, and despite the unusualness of a consort accompanying the king further than the capital, Frederick William wanted to introduce the queen as well to their people. Louise was received everywhere with festivities. For the first time in Prussian history, the queen emerged as a celebrated public personality in her own right, as she occupied a much more prominent role than her predecessors. Louise's presence on her husband's eastern journey was a break from the traditional role of the consort – importantly however the queen's power and enduring legacy did not stem from holding a separate court and policy than her husband's, but rather the opposite: she subordinated her formidable intelligence and skill for her husband's sole advantage. She also became a fashion icon, for instance starting a trend by wearing a neckerchief to keep from getting ill.

After her husband's accession, Louise developed many ties to senior ministers and became a powerful figure within the government as she began to command universal respect and affection. The queen went out of her way to stay informed about political developments at court, and from the very beginning of his reign the new king consulted Louise on matters of state. Frederick William was hesitant and cautious, and hated war, stating in 1798, "I abhor war and... know of nothing greater on earth than the preservation of peace and tranquility as the only system suited to the happiness of human kind". In keeping with the later foreign policy of his father's, Frederick William favored neutrality during the early years of the conflict with the revolutionary French First Republic, which evolved into the Napoleonic Wars (1803–15); he refused the various pressures to pick a side in the War of the Second Coalition. Louise supported this view, warning that if Prussia were to side with the coalition powers of Austria, Great Britain, and Russia, it would lead to dependence on the latter power for military support. She foresaw that because Prussia was by far the weakest of the great powers, and it would not have been able to ensure it benefited from the results of such an alliance. French aggression caused the king to eventually consider entering the wars, but his indecision prevented him from choosing a side, either France or the coalition powers. He consulted the many differing opinions of Queen Louise and his ministers, and was eventually compelled into an alliance with Napoleon, who was recently victorious from the Battle of Austerlitz (1805).

Baron vom Stein, a member of the bureaucracy, having abhorred the country's former neutrality, sought to reform the organization of the government from favor-based cronyism into a responsible ministerial government. He prepared a document for the king detailing in strong language what administrative reforms were needed, such as establishing clearer lines of responsibility among ministers; this work however never reached Frederick William, as Stein passed it first to General Ernst von Rüchel, who in turn passed it onto the queen in the spring of 1806. Though Louise agreed with its contents, she thought it "too violent and passionate" for the king, and consequently helped suppress it.

### War with France

Among the king's advisers, members of his family, such as the queen (an open advocate of war) and Prince Louis Ferdinand, led the militaristic faction in favor of war against France; those against neutrality but in favor of reform were led by Baron vom Stein and Karl August von Hardenberg. Knowing the temperament of the king, Hardenberg appealed directly to the queen for desired reform – wisely as it turned out, as Frederick William viewed the demands to remove his trusted advisers in the Kabinett as a "mutiny" similar to the Fronde.

Though Prussia had not fought in a war since 1795, its military leaders confidently expected that they could win against Napoleon's troops. After a small incident concerning an anti-French pamphlet occurred, King Frederick William was finally pressured by his wife and family to break off his uneasy peace and enter the war against the French emperor. Prussian troops began mobilizing, culminating in the October 1806 Battle of Jena-Auerstedt, which was a disaster for Prussia, as the ability of its armed forces to continue the war were effectively wiped out. The king and queen had accompanied their troops into battle at Jena (with Louise apparently dressed "like an Amazon"), but had to flee from French troops.

Napoleon himself occupied Berlin, causing the king, queen and the rest of the royal family to flee, despite Louise's illness, in the dead of winter to Memel in the easternmost part of the kingdom. On the journey there, there was no food or clean water, and the king and queen were forced to share the same sleeping arrangements in "one of the wretched barns they call houses", according to one witness traveling with them.

After various events took place, Napoleon demanded, from a highly superior position, peace terms in what was to be called the Peace of Tilsit (1807). In the midst of these negotiations, the emperor agreed to keep half of Prussia intact. The men were joined by Queen Louise; Frederick William had sent for his wife, then pregnant with her daughter Princess Louise, to beg for a better settlement for Prussia, with Louise advising her husband, "For God's sake no shameful peace...[Prussia] should at least not go down without honor." As the king felt that her presence might put Napoleon in a "more relaxed mood"; Louise reluctantly agreed to meet the emperor at Tilsit, but only to save Prussia. Napoleon had previously attempted to destroy her reputation by questioning Louise's marital fidelity, but the queen met him anyway, attempting to use her beauty and charm to flatter him into more favorable terms. Formerly Louise had regularly referred to him as "the Monster", but nevertheless made a request for a private interview with the emperor, whereon she threw herself at his feet; though he was impressed by her grace and determination, Napoleon refused to make any concessions, writing back to his wife Empress Joséphine that Louise "is really charming and full of coquettishness toward me. But don't be jealous...it would cost me too dearly to play the gallant." Napoleon's attempts to destroy Louise's reputation failed however, and they only made her more beloved in Prussia. Queen Louise's efforts to protect her adopted country from French aggression secured for her the admiration of future generations.

### Remaining years

Harsh restrictions were imposed on Prussia, such as a massive indemnity of one hundred and twenty million francs and the quartering of troops. At the time, one hundred and twenty million francs was equivalent to the entire yearly budget of Prussia. As the perceived symbol of Prussia's former grandeur and pride, the French occupation of Prussia had a particularly devastating effect upon Louise, as the queen endured personal insults – Napoleon himself gave her a backhanded compliment when he called her "the only real man in Prussia". The queen recognized that her adopted country depended on her for moral strength, and as a consequence Louise regained her old sense of optimism, often taking time to prepare their eldest son for his future role as king. In the following few years Louise supported the reforming efforts of government carried out by Stein and Hardenberg, as well as those of Gerhard von Scharnhorst and August Neidhardt von Gneisenau, to reorganize the army. After the disaster at Tilsit, Louise was instrumental in Stein's reappointment (the king had previously dismissed him), telling Frederick William "[Stein] is my last hope. A great heart, an encompassing mind, perhaps he knows remedies that are hidden to us."

By 1808 it was still considered unsafe to return to Berlin, and the royal family consequently spent the summer near Königsberg; Louise believed that the hard trials of her children's early lives would be good for them: "If they had been reared in luxury and prosperity they might think that so it must always be." In the winter of 1808, Tsar Alexander I invited the king and queen to St. Petersburg, where she was treated to sumptuously decorated rooms; "Nothing dazzles me anymore", she exclaimed on her return to Germany. Near the birth of her youngest child Princess Louise in 1809, Louise wrote to her father, "Gladly...the calamities which have befallen us have not forced their way into our wedded and home life, rather have strengthened the same, and made it even more precious to us." Louise was sick for much of that year, but returned with the king to Berlin near the end of it after an absence of three years; the queen arrived in a carriage accompanied by her two daughters Charlotte and Alexandrine and younger son Charles, and was greeted by her father at Charlottenburg Palace – the residence was ransacked however, as Napoleon and his commanders had stripped its rooms of paintings, statues, manuscripts, and antiquities. Returning to a much different Prussia than she left, a preacher observed that "our dear queen is far from joyful, but her seriousness has a quiet serenity... her eyes have lost their former sparkle, and one sees that they have wept much, and still weep".

On 19 July 1810, while visiting her father in Strelitz, the Queen died in her husband's arms from an unidentified illness. Lieutenant-General Baron De Marbot, in his Memoirs, records that the Queen in later life always wore a thick wrapping around her neck. It was to conceal a botched operation for goitre, which left an open sore, which eventually killed her. The queen's subjects attributed the French occupation as the cause of her early death. "Our saint is in heaven", exclaimed Prussian general Gebhard Leberecht von Blücher. Louise's untimely death left her husband alone during a period of great difficulty, as the Napoleonic Wars and need for reform continued. Louise was buried in the garden of Charlottenburg Palace, where a mausoleum, containing a fine recumbent statue by Christian Daniel Rauch, was built over her grave. Frederick William did not remarry until 1824, when he entered into a morganatic marriage with his mistress Auguste von Harrach, explaining "Womanly companionship and sympathy have become necessary to me, therefore I must marry again." After his death on 7 June 1840, Frederick William was buried by her side.

## Legacy

Queen Louise was revered by her subjects as the "soul of national virtue", and some historians have written that Louise was "Prussian nationalism personified." According to Christopher Clark, Louise was "a female celebrity who in the mind of the public combined virtue, modesty, and sovereign grace with kindness and sex appeal, and whose early death in 1810 at the age of only thirty-four preserved her youth in the memory of posterity." Her reputation as a loving and loyal supporter of her husband became crucial to her enduring legacy; the cult that eventually surrounded Louise became associated with the "ideal" feminine attributes: prettiness, sweet nature, maternal kindness, and wifely virtue.

On the anniversary of her birth, in 1814, the widowed King Frederick William instituted the Order of Louise (Luisenorden) as a complementary decoration for the Iron Cross. Its purpose was to be given to those women who had made a significant contribution to the war effort against Napoleon, though it was subsequently awarded to future members of the House of Hohenzollern unrelated to the French emperor, such as her granddaughter-in-law, Empress Victoria of Germany, and her great-granddaughter, Queen Sophia of Greece. In 1880 a statue of Queen Louise was erected in the Tiergarten in Berlin.

Louise inspired the establishment of a conservative women's organization known as Königin-Luise-Bund, often shortened to Luisenbund ("Queen Louise League") in which her person achieved an almost cult-like status. The group's main purpose was to promote patriotic feelings among German women, and it emphasized the family and German morality. The Königin-Luise-Bund was active during the time of the Weimar Republic and the first years of Nazi Germany. Despite having actively supported the National Socialist movement since its early stages all through their accession to power in 1933, the Queen Louise League was nonetheless disbanded by the Nazis in 1934, as they viewed it as a hostile organization.

### Popular culture

The character of Queen Louise was the popular subject of countless films released in German cinema. These included Der Film von der Königin Luise (1913), Die elf schillschen Offiziere (1926), and Vivat – Königin Luise im Fichtelgebirge (2005), Luise – Königin der Herzen (2010 documentary). She was played by Mady Christians in the 1927 silent film Queen Louise, by Henny Porten in Louise, Queen of Prussia (1931) and by Ruth Leuwerik in the 1957 film Queen Louise.

She was also briefly portrayed in an extremely reverential manner in the 1945 propaganda film Kolberg. The 1951 film The African Queen involves a British covert mission to sink the Königin Luise ("Queen Louise"), a German warship patrolling Lake Victoria at the start of World War I.

Louise became the subject of a series of novels by 19th century German historical fiction writer Luise Mühlbach, which included Louisa of Prussia and her Times and Napoleon and the Queen of Prussia.

## Issue

By Frederick William III of Prussia (3 August 1770 – 7 June 1840); married on 24 December 1793.

## Ancestry

Queen consort of Prussia (1776–1810)

Burials at the Charlottenburg Palace Park Mausoleum, Berlin


2019 redefinition of the SI base units

In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artifacts such as the standard kilogram. Effective 20 May 2019, the 144th anniversary of the Metre Convention, the kilogram, ampere, kelvin, and mole are now defined by setting exact numerical values, when expressed in SI units, for the Planck constant (h), the elementary electric charge (e), the Boltzmann constant (kB), and the Avogadro constant (NA), respectively. The second, metre, and candela had previously been redefined using physical constants. The four new definitions aimed to improve the SI without changing the value of any units, ensuring continuity with existing measurements. In November 2018, the 26th General Conference on Weights and Measures (CGPM) unanimously approved these changes, which the International Committee for Weights and Measures (CIPM) had proposed earlier that year after determining that previously agreed conditions for the change had been met. These conditions were satisfied by a series of experiments that measured the constants to high accuracy relative to the old SI definitions, and were the culmination of decades of research.

The previous major change of the metric system occurred in 1960 when the International System of Units (SI) was formally published. At this time the metre was redefined: the definition was changed from the prototype of the metre to a certain number of wavelengths of a spectral line of a krypton-86 radiation, making it derivable from universal natural phenomena. The kilogram remained defined by a physical prototype, leaving it the only artifact upon which the SI unit definitions depend. At this time the SI, as a coherent system, was constructed around seven base units, powers of which were used to construct all other units. With the 2019 redefinition, the SI is constructed around seven defining constants, allowing all units to be constructed directly from these constants. The designation of base units is retained but is no longer essential to define the SI units.

The metric system was originally conceived as a system of measurement that was derivable from unchanging phenomena, but practical limitations necessitated the use of artifacts – the prototype of the metre and prototype of the kilogram – when the metric system was introduced in France in 1799. Although it was designed for long-term stability, the masses of the prototype kilogram and its secondary copies have shown small variations relative to each other over time; they are not thought to be adequate for the increasing accuracy demanded by science, prompting a search for a suitable replacement. The definitions of some units were defined by measurements that are difficult to precisely realise in a laboratory, such as the kelvin, which was defined in terms of the triple point of water. With the 2019 redefinition, the SI became wholly derivable from natural phenomena with most units being based on fundamental physical constants.

A number of authors have published criticisms of the revised definitions; their criticisms include the premise that the proposal failed to address the impact of breaking the link between the definition of the dalton and the definitions of the kilogram, the mole, and the Avogadro constant.

## Background

The basic structure of the SI was developed over about 170 years between 1791 and 1960. Since 1960, technological advances have made it possible to address weaknesses in the SI such as the dependence on a physical artifact to define the kilogram.

### Development of SI

During the early years of the French Revolution, the leaders of the French National Constituent Assembly decided to introduce a new system of measurement that was based on the principles of logic and natural phenomena. The metre was defined as one ten-millionth of the distance from the north pole to the equator and the kilogram as the mass of one thousandth of a cubic metre of pure water. Although these definitions were chosen to avoid ownership of the units, they could not be measured with sufficient convenience or precision to be of practical use. Instead, realisations were created in the form of the mètre des Archives and kilogramme des Archives which were a "best attempt" at fulfilling these principles.

By 1875, use of the metric system had become widespread in Europe and in Latin America; that year, twenty industrially developed nations met for the Convention of the Metre, which led to the signing of the Treaty of the Metre, under which three bodies were set up to take custody of the international prototypes of the kilogram and the metre, and to regulate comparisons with national prototypes. They were:

- CGPM (General Conference on Weights and Measures, Conférence générale des poids et mesures) – The Conference meets every four to six years and consists of delegates of the nations that had signed the convention. It discusses and examines the arrangements required to ensure the propagation and improvement of the International System of Units and it endorses the results of new fundamental metrological determinations.
- CIPM (International Committee for Weights and Measures, Comité international des poids et mesures) – The Committee consists of eighteen eminent scientists, each from a different country, nominated by the CGPM. The CIPM meets annually and is tasked with advising the CGPM. The CIPM has set up a number of sub-committees, each charged with a particular area of interest. One of these, the Consultative Committee for Units (CCU), advises the CIPM on matters concerning units of measurement.
- BIPM (International Bureau for Weights and Measures, Bureau international des poids et mesures) – The Bureau provides safe keeping of the international prototypes of the kilogram and the metre, provides laboratory facilities for regular comparisons of the national prototypes with the international prototype, and is the secretariat for the CIPM and the CGPM.

The 1st CGPM (1889) formally approved the use of 40 prototype metres and 40 prototype kilograms made by the British firm Johnson Matthey as the standards mandated by the Convention of the Metre. The prototypes Metre No. 6 and Kilogram KIII were designated as the international prototype of the metre and the kilogram, respectively; the CGPM retained other copies as working copies, and the rest were distributed to member states for use as their national prototypes. About once every 40 years, the national prototypes were compared with and recalibrated against the international prototype.

In 1921 the Convention of the Metre was revised and the mandate of the CGPM was extended to provide standards for all units of measure, not just mass and length. In the ensuing years, the CGPM took on responsibility for providing standards of electrical current (1946), luminosity (1946), temperature (1948), time (1956), and molar mass (1971). The 9th CGPM in 1948 instructed the CIPM "to make recommendations for a single practical system of units of measurement, suitable for adoption by all countries adhering to the Metre Convention". The recommendations based on this mandate were presented to the 11th CGPM (1960), where they were formally accepted and given the name "Système International d'Unités" and its abbreviation "SI".

### Impetus for change

There is a precedent for changing the underlying principles behind the definition of the SI base units; the 11th CGPM (1960) defined the SI metre in terms of the wavelength of krypton-86 radiation, replacing the pre-SI metre bar, and the 13th CGPM (1967) replaced the original definition of the second, which was based on Earth's average rotation from 1750 to 1892, with a definition based on the frequency of the radiation emitted or absorbed with a transition between two hyperfine levels of the ground state of the caesium-133 atom. The 17th CGPM (1983) replaced the 1960 definition of the metre with one based on the second by giving an exact definition of the speed of light in units of metres per second.

Since their manufacture, drifts of up to 2×10−8 kilograms (20 μg) per year in the national prototype kilograms relative to the international prototype of the kilogram (IPK) have been detected. There was no way of determining whether the national prototypes were gaining mass or whether the IPK was losing mass. Newcastle University metrologist Peter Cumpson has since identified mercury vapour absorption or carbonaceous contamination as possible causes of this drift. At the 21st meeting of the CGPM (1999), national laboratories were urged to investigate ways of breaking the link between the kilogram and a specific artifact.

Metrologists investigated several alternative approaches to redefining the kilogram based on fundamental physical constants. Among others, the Avogadro project and the development of the Kibble balance (known as the "watt balance" before 2016) promised methods of indirectly measuring mass with very high precision. These projects provided tools that enable alternative means of redefining the kilogram.

A report published in 2007 by the Consultative Committee for Thermometry (CCT) to the CIPM noted that their current definition of temperature has proved to be unsatisfactory for temperatures below 20 K and for temperatures above 1300 K. The committee took the view that the Boltzmann constant provided a better basis for temperature measurement than did the triple point of water because it overcame these difficulties.

At its 23rd meeting (2007), the CGPM mandated the CIPM to investigate the use of natural constants as the basis for all units of measure rather than the artifacts that were then in use. The following year this was endorsed by the International Union of Pure and Applied Physics (IUPAP). At a meeting of the CCU held in Reading, United Kingdom, in September 2010, a resolution and draft changes to the SI brochure that were to be presented to the next meeting of the CIPM in October 2010 were agreed to in principle. The CIPM meeting of October 2010 found "the conditions set by the General Conference at its 23rd meeting have not yet been fully met. For this reason the CIPM does not propose a revision of the SI at the present time". The CIPM, however, presented a resolution for consideration at the 24th CGPM (17–21 October 2011) to agree to the new definitions in principle, but not to implement them until the details had been finalised. This resolution was accepted by the conference, and in addition the CGPM moved the date of the 25th meeting forward from 2015 to 2014. At the 25th meeting on 18 to 20 November 2014, it was found that "despite [progress in the necessary requirements] the data do not yet appear to be sufficiently robust for the CGPM to adopt the revised SI at its 25th meeting", thus postponing the revision to the next meeting in 2018. Measurements accurate enough to meet the conditions were available in 2017 and the redefinition was adopted at the 26th CGPM (13–16 November 2018).

## Defining constants

Following the successful 1983 redefinition of the metre in terms of an exact numerical value for the speed of light, the BIPM's Consultative Committee for Units (CCU) recommended and the BIPM proposed that four further constants of nature should be defined to have exact values. These are:

- The Planck constant h is exactly 6.62607015×10−34 joule-second (J⋅s).
- The elementary charge e is exactly 1.602176634×10−19 coulomb (C).
- The Boltzmann constant k is exactly 1.380649×10−23 joule per kelvin (J⋅K−1).
- The Avogadro constant NA is exactly 6.02214076×1023 reciprocal mole (mol−1).

The redefinition retains unchanged the numerical values associated with the following constants of nature:

- The speed of light c is exactly 299792458 metres per second (m⋅s−1);
- The ground state hyperfine structure transition frequency of the caesium-133 atom ΔνCs is exactly 9192631770 hertz (Hz);
- The luminous efficacy of monochromatic radiation of frequency 540×1012 Hz (540 THz) – a frequency of green-colored light at approximately the peak sensitivity of the human eye – Kcd (where the subscript "cd" is the symbol for candela) is exactly 683 lumens per watt (lm⋅W−1).

The seven SI defining constants above, expressed in terms of derived units (joule, coulomb, hertz, lumen, and watt), are rewritten below in terms of the seven base units (second, metre, kilogram, ampere, kelvin, mole, and candela); the dimensionless unit steradian (symbol sr) is also used:

- ΔνCs = Δν(133Cs)hfs = 9192631770 s−1
- c = 299792458 m⋅s−1
- h = 6.62607015×10−34 kg⋅m2⋅s−1
- e = 1.602176634×10−19 A⋅s
- k = 1.380649×10−23 kg⋅m2⋅K−1⋅s−2
- NA = 6.02214076×1023 mol−1
- Kcd = 683 cd⋅sr⋅s3⋅kg−1⋅m−2

As part of the redefinition, the International Prototype of the Kilogram was retired and definitions of the kilogram, the ampere, and the kelvin were replaced. The definition of the mole was revised. These changes have the effect of redefining the SI base units, though the definitions of the SI derived units in terms of the base units remain the same.

## Impact on base unit definitions

Following the CCU proposal, the texts of the definitions of all of the base units were either refined or rewritten, changing the emphasis from explicit-unit- to explicit-constant-type definitions. Explicit-unit-type definitions define a unit in terms of a specific example of that unit; for example, in 1324 Edward II defined the inch as being the length of three barleycorns, and from 1889 to 2019 the kilogram was defined as the mass of the International Prototype of the Kilogram. In explicit-constant definitions, a constant of nature is given a specified value, and the definition of the unit emerges as a consequence; for example, in 2019, the speed of light was defined as exactly 299792458 metres per second. The length of the metre could be derived because the second had been already independently defined. The previous and 2019 definitions are given below.

### Second

The new definition of the second is effectively the same as the previous one, the only difference being that the conditions under which the definition applies are more rigorously defined.

- Previous definition: The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
- 2019 definition: The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.

The second may be expressed directly in terms of the defining constants:

1 s = 9192631770/ΔνCs.

### Metre

The new definition of the metre is effectively the same as the previous one, the only difference being that the additional rigour in the definition of the second propagated to the metre.

- Previous definition: The metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second.
- 2019 definition: The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299792458 when expressed in the unit m⋅s−1, where the second is defined in terms of the caesium frequency ΔνCs.

The metre may be expressed directly in terms of the defining constants:

1 m = 9192631770/299792458c/ΔνCs.

### Kilogram

The definition of the kilogram fundamentally changed from an artifact (the International Prototype of the Kilogram) to a constant of nature. The new definition relates the kilogram to the mass equivalent of the energy of a photon at a specific frequency.

- Previous definition: The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.
- 2019 definition: The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015×10−34 when expressed in the unit J⋅s, which is equal to kg⋅m2⋅s−1, where the metre and the second are defined in terms of c and ΔνCs.

For illustration, an earlier proposed redefinition that is equivalent to this 2019 definition is: "The kilogram is the mass of a body at rest whose equivalent energy equals the energy of a collection of photons whose frequencies sum to [1.356392489652×1050] hertz."

The kilogram may be expressed directly in terms of the defining constants:

1 kg = (299792458)2/(6.62607015×10−34)(9192631770)/c2.

Leading to

1 J⋅s = h/6.62607015×10−34

1 J = /(6.62607015×10−34)(9192631770)

1 W = /(6.62607015×10−34)(9192631770)2

1 N =

### Ampere

The definition of the ampere underwent a major revision. The previous definition, which is difficult to realise with high precision in practice, was replaced by a definition that is easier to realise.

- Previous definition: The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2×10−7 newton per metre of length.
- 2019 definition: The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602176634×10−19 when expressed in the unit C, which is equal to A⋅s, where the second is defined in terms of ΔνCs.

The ampere may be expressed directly in terms of the defining constants as:

1 A = /(1.602176634×10−19)(9192631770)

For illustration, this is equivalent to defining one coulomb to be an exact specified multiple of the elementary charge.

1 C = e/1.602176634×10−19

Because the previous definition contains a reference to force, which has the dimensions MLT−2, it follows that in the previous SI the kilogram, metre, and second – the base units representing these dimensions – had to be defined before the ampere could be defined. Other consequences of the previous definition were that in SI the value of vacuum permeability (μ0) was fixed at exactly 4π×10−7 H⋅m−1. Because the speed of light in vacuum (c) is also fixed, it followed from the relationship $c^2=\frac{1}{\mu_0\varepsilon_0}$ that the vacuum permittivity (ε0) had a fixed value, and from $Z_0=\sqrt{\frac{\mu_0}{\varepsilon_0}} ,$ that the impedance of free space (Z0) likewise had a fixed value.

A consequence of the revised definition is that the ampere no longer depends on the definitions of the kilogram and the metre; it does, however, still depend on the definition of the second. In addition, the numerical values when expressed in SI units of the vacuum permeability, vacuum permittivity, and impedance of free space, which were exact before the redefinition, are subject to experimental error after the redefinition. For example, the numerical value of the vacuum permeability has a relative uncertainty equal to that of the experimental value of the fine-structure constant $\alpha$. The CODATA 2018 value for the relative standard uncertainty of $\alpha$ is

The ampere definition leads to exact values for

1 V =

1 Wb =

1 Ω =

### Kelvin

The definition of the kelvin underwent a fundamental change. Rather than using the triple point of water to fix the temperature scale, the new definition uses the energy equivalent as given by Boltzmann's equation.

- Previous definition: The kelvin, unit of thermodynamic temperature, is 1/273.16 of the thermodynamic temperature of the triple point of water.
- 2019 definition: The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant k to be 1.380649×10−23 when expressed in the unit J⋅K−1, which is equal to kg⋅m2⋅s−2⋅K−1, where the kilogram, metre and second are defined in terms of h, c and ΔνCs.

The kelvin may be expressed directly in terms of the defining constants as:

1 K = 1.380649×10−23/(6.62607015×10−34)(9192631770)/k.

### Mole

The previous definition of the mole linked it to the kilogram. The revised definition breaks that link by making a mole a specific number of entities of the substance in question.

- Previous definition: The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
- 2019 definition: The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.02214076×1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in the unit mol−1 and is called the Avogadro number. The amount of substance, symbol n, of a system is a measure of the number of specified elementary entities. An elementary entity may be an atom, a molecule, an ion, an electron, any other particle or specified group of particles.

The mole may be expressed directly in terms of the defining constants as:

1 mol = 6.02214076×1023/NA.

One consequence of this change is that the previously defined relationship between the mass of the 12C atom, the dalton, the kilogram, and the Avogadro constant is no longer valid. One of the following had to change:

- The mass of a 12C atom is exactly 12 dalton.
- The number of dalton in a gram is exactly the numerical value of the Avogadro constant: (i.e., 1 g/Da = 1 mol ⋅ NA).

The wording of the 9th SI Brochure implies that the first statement remains valid, which means the second is no longer true. The molar mass constant, while still with great accuracy remaining 1 g/mol, is no longer exactly equal to that. Appendix 2 to the 9th SI Brochure states that "the molar mass of carbon 12, M(12C), is equal to 0.012 kg⋅mol−1 within a relative standard uncertainty equal to that of the recommended value of NAh at the time this Resolution was adopted, namely 4.5×10−10, and that in the future its value will be determined experimentally", which makes no reference to the dalton and is consistent with either statement.

### Candela

The new definition of the candela is effectively the same as the previous definition as dependent on other base units, with the result that the redefinition of the kilogram and the additional rigour in the definitions of the second and metre propagate to the candela.

- Previous definition: The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 Hz and that has a radiant intensity in that direction of 1/683 watt per steradian.
- 2019 definition: The candela, symbol cd, is the SI unit of luminous intensity in a given direction. It is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540×1012 Hz, Kcd, to be 683 when expressed in the unit lm⋅W−1, which is equal to cd⋅sr⋅W−1, or cd⋅sr⋅kg−1⋅m−2⋅s3, where the kilogram, metre and second are defined in terms of h, c and ΔνCs.

1 cd =

## Impact on reproducibility

All seven of the SI base units are defined in terms of defined constants and universal physical constants. Seven constants are needed to define the seven base units but there is not a direct correspondence between each specific base unit and a specific constant; except the second and the mole, more than one of the seven constants contributes to the definition of any given base unit.

When the New SI was first designed, there were more than six suitable physical constants from which the designers could choose. For example, once length and time had been established, the universal gravitational constant G could, from a dimensional point of view, be used to define mass. In practice, G can only be measured with a relative uncertainty of the order of 10−5, which would have resulted in the upper limit of the kilogram's reproducibility being around 10−5 whereas the then-current international prototype of the kilogram can be measured with a reproducibility of 1.2 × 10−8. The physical constants were chosen on the basis of minimal uncertainty associated with measuring the constant and the degree of independence of the constant in respect of other constants that were being used. Although the BIPM has developed a standard mise en pratique (practical technique) for each type of measurement, the mise en pratique used to make the measurement is not part of the measurement's definition – it is merely an assurance that the measurement can be done without exceeding the specified maximum uncertainty.

## Acceptance

Much of the work done by the CIPM is delegated to consultative committees. The CIPM Consultative Committee for Units (CCU) has made the proposed changes while other committees have examined the proposal in detail and have made recommendations regarding their acceptance by the CGPM in 2014. The consultative committees have laid down a number of criteria that must be met before they will support the CCU's proposal, including:

- For the redefinition of the kilogram, at least three separate experiments yielding values for the Planck constant having a relative expanded (95%) uncertainty of no more than 5×10−8 must be carried out and at least one of these values should be better than 2×10−8. Both the Kibble balance and the Avogadro project should be included in the experiments and any differences between these must be reconciled.
- For the redefinition of the kelvin, the relative uncertainty of the Boltzmann constant derived from two fundamentally different methods such as acoustic gas thermometry and dielectric constant gas thermometry must be better than 10−6, and these values must be corroborated by other measurements.

As of March 2011, the International Avogadro Coordination (IAC) group had obtained an uncertainty of 3.0×10−8 and NIST had obtained an uncertainty of 3.6×10−8 in their measurements. On 1 September 2012 the European Association of National Metrology Institutes (EURAMET) launched a formal project to reduce the relative difference between the Kibble balance and the silicon sphere approach to measuring the kilogram from (17±5)×10−8 to within 2×10−8. As of March 2013 the proposed redefinition is known as the "New SI" but Mohr, in a paper following the CGPM proposal but predating the formal CCU proposal, suggested that because the proposed system makes use of atomic scale phenomena rather than macroscopic phenomena, it should be called the "Quantum SI System".

As of the 2014 CODATA-recommended values of the fundamental physical constants published in 2016 using data collected until the end of 2014, all measurements met the CGPM's requirements, and the redefinition and the next CGPM quadrennial meeting in late 2018 could now proceed.

On 20 October 2017, the 106th meeting of the International Committee for Weights and Measures (CIPM) formally accepted a revised Draft Resolution A, calling for the redefinition of the SI, to be voted on at the 26th CGPM, The same day, in response to the CIPM's endorsement of the final values, the CODATA Task Group on Fundamental Constants published its 2017 recommended values for the four constants with uncertainties and proposed numerical values for the redefinition without uncertainty. The vote, which was held on 16 November 2018 at the 26th GCPM, was unanimous; all attending national representatives voted in favour of the revised proposal.

The new definitions became effective on 20 May 2019.

## Concerns

In 2010, Marcus Foster of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) published a wide-ranging critique of the SI; he raised numerous issues ranging from basic issues such as the absence of the symbol "Ω" (Omega, for the ohm) from most Western computer keyboards to abstract issues such as inadequate formalism in the metrological concepts on which SI is based. The changes proposed in the new SI only addressed problems with the definition of the base units, including new definitions of the candela and the mole – units Foster argued are not true base units. Other issues raised by Foster fell outside the scope of the proposal.

### Explicit-unit and explicit-constant definitions

Concerns have been expressed that the use of explicit-constant definitions of the unit being defined that are not related to an example of its quantity will have many adverse effects. Although this criticism applies to the linking of the kilogram to the Planck constant h via a route that requires a knowledge of both special relativity and quantum mechanics, it does not apply to the definition of the ampere, which is closer to an example of its quantity than is the previous definition. Some observers have welcomed the change to base the definition of electric current on the charge of the electron rather than the previous definition of a force between two parallel, current-carrying wires; because the nature of the electromagnetic interaction between two bodies is somewhat different at the quantum electrodynamics level than at classical electrodynamic levels, it is considered inappropriate to use classical electrodynamics to define quantities that exist at quantum electrodynamic levels.

### Mass and the Avogadro constant

When the scale of the divergence between the IPK and national kilogram prototypes was reported in 2005, a debate began about whether the kilogram should be defined in terms of the mass of the silicon-28 atom or by using the Kibble balance. The mass of a silicon atom could be determined using the Avogadro project and using the Avogadro constant, it could be linked directly to the kilogram. Concerns that the authors of the proposal had failed to address the impact of breaking the link between the mole, kilogram, dalton, and the Avogadro constant (NA) have also been expressed. This direct link has caused many to argue that the mole is not a true physical unit but, according to the Swedish philosopher Johansson, a "scaling factor".

The 8th edition of the SI Brochure defined the dalton in terms of the mass of an atom of 12C. It defined the Avogadro constant in terms of this mass and the kilogram, making it determined by experiment. The redefinition fixes the Avogadro constant and the 9th SI Brochure retains the definition of dalton in terms of 12C, with the effect that the link between the dalton and the kilogram will be broken.

In 1993, the International Union of Pure and Applied Chemistry (IUPAC) approved the use of the dalton as an alternative to the unified atomic mass unit with the qualification that the CGPM had not given its approval. This approval has since been given. Following the proposal to redefine the mole by fixing the value of the Avogadro constant, Brian Leonard of the University of Akron, writing in Metrologia, proposed that the dalton (Da) be redefined such that NA = (g/Da) mol−1, but that the unified atomic mass unit (mu) retain its current definition based on the mass of 12C, ceasing to exactly equal the dalton. This would result in the dalton and the atomic mass unit potentially differing from each other with a relative uncertainty of the order of 10−10. The 9th SI Brochure, however, defines both the dalton (Da) and the unified atomic mass unit (u) as exactly 1/12 of the mass of a free carbon-12 atom and not in relation to the kilogram, with the effect that the above equation will be inexact.

### Temperature

Different temperature ranges need different measurement methods. Room temperature can be measured by means of expansion and contraction of a liquid in a thermometer but high temperatures are often associated with colour of blackbody radiation. Wojciech T. Chyla, approaching the structure of SI from a philosophical point of view in the Journal of the Polish Physical Society, argued that temperature is not a real base unit but is an average of the thermal energies of the individual particles that comprise the body concerned. He noted that in many theoretical papers, temperature is represented by the quantities Θ or β where $\Theta=k T; \quad \beta = \frac{1}{k T}$ and k is the Boltzmann constant. Chyla acknowledged, however, that in the macroscopic world, temperature plays the role of a base unit because much of the theory of thermodynamics is based on temperature.

The Consultative Committee for Thermometry, part of the International Committee for Weights and Measures, publishes a mise en pratique (practical technique), last updated in 1990, for measuring temperature. At very low and at very high temperatures it often links energy to temperature via the Boltzmann constant.

### Luminous intensity

Foster argued that "luminous intensity [the candela] is not a physical quantity, but a photobiological quantity that exists in human perception", questioning whether the candela should be a base unit. Before the 1979 decision to define photometric units in terms of luminous flux (power) rather than luminous intensities of standard light sources, there was already doubt whether there should still be a separate base unit for photometry. Furthermore, there was unanimous agreement that the lumen was now more fundamental than the candela. However, for the sake of continuity the candela was kept as base unit.

## See also

- – changes associated with the 2019 redefinition

Definition of the units kg, A, K and mol


Jonah

Jonah or Jonas, son of Amittai, is a prophet in the Hebrew Bible from Gath-hepher of the northern kingdom of Israel in about the 8th century BCE. Jonah is the central figure of the Book of Jonah, which details his reluctance in delivering God's judgement on the city of Nineveh. Subsequently he returns to the divine mission after he is swallowed by a large sea creature and then released.

In Judaism, the story of Jonah represents the teaching of teshuva, which is the ability to repent and be forgiven by God. In the New Testament, Jesus calls himself "greater than Jonah" and promises the Pharisees "the sign of Jonah", which is his resurrection. Early Christian interpreters viewed Jonah as a type for Jesus. Jonah is regarded as a prophet in Islam, and the biblical narrative of Jonah is repeated in the Quran with a chapter named after him (Yunus). Mainstream Bible scholars generally regard the Book of Jonah as fictional, and often at least partially satirical. The character of Jonah, son of Amittai may have been based on the historical prophet of the same name who prophesied during the reign of Amaziah of Judah, as mentioned in 2 Kings.

Although the creature that swallowed Jonah is often depicted in art and culture as a whale, the Hebrew text uses the phrase dag gadol, which means "big fish". In the seventeenth and early eighteenth centuries, the species of the fish that swallowed Jonah was the subject of speculation by naturalists, who interpreted the story as an account of a historical incident. Some modern scholars of folklore, on the other hand, note similarities between Jonah and other legendary religious and mythical figures, specifically Gilgamesh and the Greek hero Jason.

## Book of Jonah

Jonah is the central character in the Book of Jonah, in which God commands him to go to the city of Nineveh to prophesy against it "for their great wickedness is come up before me," but Jonah instead attempts to flee from "the presence of the Lord" by going to Jaffa (sometimes transliterated as Joppa or Joppe). He sets sail for Tarshish. A huge storm arises and the sailors, realizing that it is no ordinary storm, cast lots and discover that Jonah is to blame. Jonah admits this and says that if he is thrown overboard, the storm will cease. The sailors refuse to do this and continue rowing, but all their efforts fail, and they eventually throw Jonah overboard. As a result, the storm calms and the sailors offer sacrifices to God.

After being cast from the ship, Jonah is swallowed by a large fish, within the belly of which he remains for three days and three nights. While in the great fish, Jonah prays to God in his affliction and commits to giving thanks and to paying what he has vowed. God commands the fish to vomit Jonah out.

God again commands Jonah to travel to Nineveh and prophesy to its inhabitants. This time he travels there and enters the city, crying, "In forty days Nineveh shall be overthrown." After Jonah has walked across Nineveh, the people begin to believe his word and proclaim a fast. The king of Nineveh puts on sackcloth and sits in ashes, making a proclamation which decrees fasting, the wearing of sackcloth, prayer, and repentance. God sees their repentant hearts and spares the city at that time. The entire city is humbled and broken, with the people (and even the animals) wearing sackcloth and ashes.

Displeased by this, Jonah refers to his earlier flight to Tarshish while asserting that, since God is merciful, it was inevitable that God would turn from the threatened calamities. He leaves the city and makes a shelter, waiting to see whether or not the city will be destroyed. God causes a plant (in Hebrew a kikayon) to grow over Jonah's shelter to give him some shade from the sun. Later, God causes a worm to bite the plant's root and it withers. Jonah, exposed to the full force of the sun, becomes faint and pleads for God to kill him.

> But God said to Jonah: "Do you have a right to be angry about the vine?" And he said: "I do. I am angry enough to die."
> But the LORD said: "You have been concerned about this vine, though you did not tend it or make it grow. It sprang up overnight, and died overnight.
> But Nineveh has more than a hundred and twenty thousand people who cannot tell their right hand from their left, and many cattle as well. Should I not be concerned about that great city?"

## Religious views

### In Judaism

The Book of Jonah (Yonah יונה) is one of the twelve minor prophets included in the Tanakh. According to one tradition, Jonah was the boy brought back to life by Elijah the prophet in 1 Kings. Another tradition holds that he was the son of the woman of Shunem brought back to life by Elisha in 2 Kings and that he is called the "son of Amittai" (Truth) due to his mother's recognition of Elisha's identity as a prophet in 2 Kings. The Book of Jonah is read every year, in its original Hebrew and in its entirety, on Yom Kippur – the Day of Atonement – as the Haftarah at the afternoon mincha prayer. According to Rabbi Eliezer, the fish that swallowed Jonah was created in the primordial era and the inside of its mouth was like a synagogue; the fish's eyes were like windows and a pearl inside its mouth provided further illumination.

According to the Midrash, while Jonah was inside the fish, it told him that its life was nearly over because soon the Leviathan would eat them both. Jonah promised the fish that he would save them. Following Jonah's directions, the fish swam up alongside the Leviathan and Jonah threatened to leash the Leviathan by its tongue and let the other fish eat it. The Leviathan heard Jonah's threats, saw that he was circumcised, and realized that he was protected by the Lord, so it fled in terror, leaving Jonah and the fish alive. The medieval Jewish scholar and rabbi Abraham ibn Ezra (1092–1167) argued against any literal interpretation of the Book of Jonah, stating that the "experiences of all the prophets except Moses were visions, not actualities." The later scholar Isaac Abarbanel (1437–1509), however, argued that Jonah could have easily survived in the belly of the fish for three days, because "after all, fetuses live nine months without access to fresh air."

Teshuva – the ability to repent and be forgiven by God – is a prominent idea in Jewish thought. This concept is developed in the Book of Jonah: Jonah, the son of truth (the name of his father "Amitai" in Hebrew means truth), refuses to ask the people of Nineveh to repent. He seeks the truth only, and not forgiveness. When forced to go, his call is heard loud and clear. The people of Nineveh repent ecstatically, "fasting, including the sheep," and the Jewish scripts are critical of this. The Book of Jonah also highlights the sometimes unstable relationship between two religious needs: comfort and truth.

### In Christianity

#### In the Book of Tobit

Jonah is mentioned twice in the fourteenth chapter of the deuterocanonical Book of Tobit, the conclusion of which finds Tobit's son, Tobias, rejoicing at the news of Nineveh's destruction by Nebuchadnezzar and Ahasuerus in apparent fulfillment of Jonah's prophecy against the Assyrian capital.

#### In the New Testament

In the New Testament, Jonah is mentioned in the gospels of Matthew and Luke. In Matthew, Jesus makes a reference to Jonah when he is asked for a sign by some of the scribes and the Pharisees. Jesus says that the sign will be the sign of Jonah: Jonah's restoration after three days and three night inside the great fish prefigures His own resurrection.

> 39He answered, "A wicked and adulterous generation asks for a sign! But none will be given it except the sign of the prophet Jonah. 40For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth. 41The men of Nineveh will stand up at the judgment with this generation and condemn it; for they repented at the preaching of Jonah, and now something greater than Jonah is here."

Jonah is regarded as a saint by a number of Christian denominations. His feast day in the Roman Catholic Church is on 21 September, according to the Martyrologium Romanum. On the Eastern Orthodox liturgical calendar, Jonah's feast day is on 22 September (for those churches which follow the traditional Julian calendar; 22 September currently falls in October on the modern Gregorian calendar). In the Armenian Apostolic Church, moveable feasts are held in commemoration of Jonah as a single prophet and as one of the Twelve Minor Prophets. Jonah's mission to the Ninevites is commemorated by the Fast of Nineveh in Syriac and Oriental Orthodox Churches. Jonah is commemorated as a prophet in the Calendar of Saints of the Missouri Synod of the Lutheran Church on 22 September.

Christian theologians have traditionally interpreted Jonah as a type for Jesus Christ. Jonah being in swallowed by the giant fish was regarded as a foreshadowing of Jesus's crucifixion and Jonah emerging from the fish after three days was seen as a parallel for Jesus emerging from the tomb after three days. Saint Jerome equates Jonah with Jesus's more nationalistic side, and justifies Jonah's actions by arguing that "Jonah acts thus as a patriot, not so much that he hates the Ninevites, as that he does not want to destroy his own people."

#### Post-Biblical views

Other Christian interpreters, including Saint Augustine and Martin Luther, have taken a directly opposite approach, regarding Jonah as the epitome of envy and jealousness, which they regarded as inherent characteristics of the Jewish people. Luther likewise concludes that the kikayon represents Judaism, and that the worm which devours it represents Christ. Luther also questioned the idea that the Book of Jonah was ever intended as literal history, commenting that he found it hard to believe that anyone would have interpreted it as such if it had never been included in the Bible. Luther's antisemitic interpretation of Jonah remained the prevailing interpretation among German Protestants throughout early modern history. J. D. Michaelis comments that "the meaning of the fable hits you right between the eyes", and concludes that the Book of Jonah is a polemic against "the Israelite people's hate and envy towards all the other nations of the earth." Albert Eichhorn was a strong supporter of Michaelis's interpretation.

John Calvin and John Hooper regarded the Book of Jonah as a warning to all those who might attempt to flee from the wrath of God. While Luther had been careful to maintain that the Book of Jonah was not written by Jonah, Calvin declared that the Book of Jonah was Jonah's personal confession of guilt. Calvin sees Jonah's time inside the fish's belly as equivalent to the fires of Hell, intended to correct Jonah and set him on the path of righteousness. Also unlike Luther, Calvin finds fault with all the characters in the story, describing the sailors on the boat as "hard and iron-hearted, like Cyclops'", the penitence of the Ninevites as "untrained", and the king of Nineveh as a "novice". Hooper, on the other hand, sees Jonah as the archetypal dissident and the ship he is cast out from as a symbol of the state. Hooper deplores such dissidents, decrying: "Can you live quietly with so many Jonasses? Nay then, throw them into the sea!" In the eighteenth century, German professors were forbidden from teaching that the Book of Jonah was anything other than a literal, historical account.

### In Islam

#### Quran

Jonah (Arabic: يُونُس, romanized: Yūnus) is the title of the tenth chapter of the Quran. Yūnus is traditionally viewed as highly important in Islam as a prophet who was faithful to God and delivered His messages. Jonah is the only one of Judaism's Twelve Minor Prophets to be named in the Quran. In Quran 21:87 and 68:48, Jonah is called Dhul-Nūn (Arabic: ذُو ٱلنُّوْن; meaning "The One of the Fish"). In 4:163 and 6:86, he is referred to as "an apostle of Allah". Surah 37:139–148 retells the full story of Jonah:

> And verily, Jonah was among the messengers.
> [Mention] when he ran away to the laden ship.
> Then (to save it from sinking) he drew straws (with other passengers). He lost and was thrown overboard.
> Then the whale engulfed him while he was blameworthy.
> Had it not been that he (repented and) glorified Allah,
> He would certainly have remained inside the Fish till the Day of Resurrection.
> But We cast him onto the open (shore), (totally) worn out,
> and caused a squash plant to grow over him.
> We (later) sent him (back) to (his city of) at least one hundred thousand people,
> And they believed, so We allowed them enjoyment for a while.

The Quran never mentions Jonah's father, but Muslim tradition teaches that Jonah was from the tribe of Benjamin and that his father was Amittai.

#### Hadiths

Jonah is also mentioned in a few incidents during the lifetime of Muhammad. Quraysh sent their servant, Addas, to serve him grapes for sustenance. Muhammad asked Addas where he was from and the servant replied Nineveh. "The town of Jonah the just, son of Amittai!" Muhammad exclaimed. Addas was shocked because he knew that the pagan Arabs had no knowledge of the prophet Jonah. He then asked how Muhammad knew of this man. "We are brothers," Muhammad replied. "Jonah was a Prophet of God and I, too, am a Prophet of God." Addas immediately accepted Islam and kissed the hands and feet of Muhammad.

One of the sayings attributed to Muhammad, in the collection of Imam Bukhari, says that Muhammad said "One should not say that I am better than Jonah". Umayya ibn Abi al-Salt, an older contemporary of Muhammad, taught that, had Jonah not prayed to Allah, he would have remained trapped inside the fish until Judgement Day, but, because of his prayer, Jonah "stayed only a few days within the belly of the fish".

The ninth-century Persian historian Al-Tabari records that, while Jonah was inside the fish, "none of his bones or members were injured". Al-Tabari also writes that Allah made the body of the fish transparent, allowing Jonah to see the "wonders of the deep" and that Jonah heard all the fish singing praises to Allah. Kisai Marvazi, a tenth-century poet, records that Jonah's father was seventy years old when Jonah was born and that he died soon afterwards, leaving Jonah's mother with nothing but a wooden spoon, which turned out to be a cornucopia.

#### Claimed tombs

Nineveh's current location is marked by excavations of five gates, parts of walls on four sides, and two large mounds: the hill of Kuyunjik and hill of Nabi Yunus. A mosque atop Nabi Yunus was dedicated to the prophet Jonah and contained a shrine, which was revered by both Muslims and Christians as the site of Jonah's tomb. The tomb was a popular pilgrimage site and a symbol of unity to Jews, Christians, and Muslims across the Middle East. On July 24, 2014, the Islamic State of Iraq and the Levant (ISIL) destroyed the mosque containing the tomb as part of a campaign to destroy religious sanctuaries it deemed to be idolatrous. After Mosul was taken back from ISIL in January 2017, an ancient Assyrian palace built by Esarhaddon dating to around the first half of the 7th century BCE was discovered beneath the ruined mosque. ISIL had plundered the palace of items to sell on the black market, but some of the artifacts that were more difficult to transport still remained in place.

Other reputed locations of Jonah's tomb include:

- the Arab village of Mashhad, located on the ancient site of Gath-hepher in Israel;
- the Nabi Yunis mosque of the Palestinian town of Halhul, in the West Bank, 5 km (3.1 mi) north of Hebron, was purportedly built over Jonah's tomb;
- a sanctuary near the city of Sarafand (Sarepta) in Lebanon;
- a hill now called Giv'at Yonah, "Jonah's Hill", at the northern edge of the Israeli town of Ashdod, at a site covered by a modern lighthouse;
- a "tomb of Jonah" in the city of Diyarbakir, Turkey, located behind the mihrab at Fatih Pasha Mosque – Evliya Çelebi states in his Seyahatname that he visited the tombs of prophet Jonah and prophet George in the city.

## Scholarly interpretations

The story of a man surviving after being swallowed by a whale or giant fish is classified in the catalogue of folktale types as ATU 1889G.

### Historicity

Many Biblical scholars hold that the contents of the Book of Jonah are ahistorical. Although the prophet Jonah allegedly lived in the eighth century BCE, the Book of Jonah was written centuries later during the time of the Achaemenid Empire. The Hebrew used in the Book of Jonah shows strong influences from Aramaic and the cultural practices described in it match those of the Achaemenid Persians. Some scholars regard the Book of Jonah as an intentional work of parody or satire. If this is the case, then it was probably admitted into the canon of the Hebrew Bible by sages who misunderstood its satirical nature and mistakenly interpreted it as a serious prophetic work.

While the Book of Jonah itself is considered fiction, Jonah himself may have been a historical prophet; he is briefly mentioned in the Second Book of Kings:

> He restored the border of Israel from the entrance of Hamath unto the sea of the Arabah, according to the word of the LORD, the God of Israel, which He spoke by the hand of His servant Jonah the son of Amittai, the prophet, who was of Gath-hepher.

### Parodic elements

The views expressed by Jonah in the Book of Jonah are a parody of views held by members of Jewish society at the time when it was written. The primary target of the satire may have been a faction whom Morton Smith calls "Separationists", who believed that God would destroy those who disobeyed him, that sinful cities would be obliterated, and that God's mercy did not extend to those outside the Abrahamic covenant. McKenzie and Graham remark that "Jonah is in some ways the most 'orthodox' of Israelite theologians – to make a theological point." Jonah's statements throughout the book are characterized by their militancy, but his name ironically means "dove", a bird which the ancient Israelites associated with peace.

Jonah's rejection of God's commands is a parody of the obedience of the prophets described in other Old Testament writings. The king of Nineveh's instant repentance parodies the rulers throughout the other writings of the Old Testament who disregard prophetic warnings, such as Ahab and Zedekiah. The readiness to worship God displayed by the sailors on the ship and the people of Nineveh contrasts ironically with Jonah's own reluctance, as does Jonah's greater love for kikayon providing him shade than for all the people in Nineveh.

The Book of Jonah also employs elements of literary absurdism; it exaggerates the size of the city of Nineveh to an implausible degree and incorrectly refers to the administrator of the city as a "king". According to scholars, no human being could realistically survive for three days inside a fish, and the description of the livestock in Nineveh fasting alongside their owners is "silly".

The motif of a protagonist being swallowed by a giant fish or whale became a stock trope of later satirical writings. Similar incidents are recounted in Lucian of Samosata's A True Story, which was written in the second century CE, and in the novel Baron Munchausen's Narrative of his Marvellous Travels and Campaigns in Russia, published by Rudolf Erich Raspe in 1785.

## The fish

### Translation

Though art and culture often depicts Jonah's fish as a whale, the Hebrew text, as throughout scripture, refers to no marine species in particular, simply saying "great fish" or "big fish". While some biblical scholars suggest the size and habits of the great white shark correspond better to the representations of Jonah's experiences, normally an adult human is too large to be swallowed whole. The development of whaling from the 18th century onwards made it clear that most, if not all, species of whale could not swallow a human, leading to much controversy about the veracity of the biblical story of Jonah.

In Jonah 2:1 (1:17 in English translations), the Hebrew text reads dag gadol (דג גדול) or, in the Hebrew Masoretic Text, dāḡ gāḏōl (דָּ֣ג גָּד֔וֹל), which means "great fish". The Septuagint translates this phrase into Greek as kētei megalōi (κήτει μεγάλῳ), meaning "huge fish". In Greek mythology, the same word meaning "fish" (kêtos) is used to describe the sea monster slain by the hero Perseus that nearly devoured the Princess Andromeda. Jerome later translated this phrase as piscis grandis in his Latin Vulgate. He translated kétos, however, as ventre ceti in Matthew 12:40: this second case occurs only in this verse of the New Testament.

At some point cetus became synonymous with "whale" (the study of whales is now called cetology). In his 1534 translation, William Tyndale translated the phrase in Jonah 2:1 as "greate fyshe" and the word kétos (Greek) or cetus (Latin) in Matthew 12:40 as "whale". Tyndale's translation was later incorporated into the Authorized Version of 1611. Since then, the "great fish" in Jonah 2 has been most often interpreted as a whale. In English some translations use the word "whale" for Matthew 12:40, while others use "sea creature" or "big fish".

### Scientific speculation

In the seventeenth and eighteenth centuries, naturalists, interpreting the Jonah story as a historical account, became obsessed with trying to identify the exact species of the fish that swallowed Jonah. In the mid-nineteenth century, Edward Bouverie Pusey, professor of Hebrew at Oxford University, claimed that the Book of Jonah must have been authored by Jonah himself and argued that the fish story must be historically true, or else it would not have been included in the Bible. Pusey attempted to scientifically catalogue the fish, hoping to "shame those who speak of the miracle of Jonah's preservation in the fish as a thing less credible than any of God's other miraculous doings".

The debate over the fish in the Book of Jonah played a major role during Clarence Darrow's cross-examination of William Jennings Bryan at the Scopes Trial in 1925. Darrow asked Bryan "When you read that ... the whale swallowed Jonah ... how do you literally interpret that?" Bryan replied that he believed in "a God who can make a whale and can make a man and make both of them do what He pleases." Bryan ultimately admitted that it was necessary to interpret the Bible, and is generally regarded as having come off looking like a "buffoon".

The largest of all whales – blue whales – are baleen whales which eat plankton; and "it is commonly said that this species would be choked if it attempted to swallow a herring." As for the whale shark, Dr. E. W. Gudger, an Honorary Associate in Ichthyology at the American Museum of Natural History, notes that, while the whale shark does have a large mouth, its throat is only four inches wide, with a sharp elbow or bend behind the opening, meaning that not even a human arm would be able to pass through it. He concludes that "the whale shark is not the fish that swallowed Jonah."

Sperm whales, however, appear to be a different matter: They regularly eat giant squid, so presumably one could swallow a human. Similar to a cow, sperm whales have four-chambered stomachs. The first chamber has no gastric juices but has muscular walls to crush its food. On the other hand, it is not possible to breathe inside the sperm whale's stomach because there is no air (but probably methane instead).

## Cultural influence

In Turkish, "Jonah's fish" (yunus balığı) is the term used for dolphins. A long-established expression among sailors uses the term "a Jonah" to mean a sailor/passenger whose presence on board brings bad luck and endangers the ship. Later, this meaning was extended to "a person who carries a jinx, one who will bring bad luck to any enterprise."

Despite its brevity, the Book of Jonah has been adapted numerous times in literature and in popular culture. In Herman Melville's Moby-Dick (1851), Father Mapple delivers a sermon on the Book of Jonah. Mapple asks why Jonah does not show remorse for disobeying God while he is inside of the fish. He comes to the conclusion that Jonah admirably understands that "his dreadful punishment is just." Carlo Collodi's The Adventures of Pinocchio (1883) features the title character and his father Geppetto being swallowed by "the Terrible Dogfish," an allusion to the story of Jonah. Walt Disney's 1940 film adaptation of the novel retains this allusion. The story of Jonah was adapted into Phil Vischer and Mike Nawrocki's animated film Jonah: A VeggieTales Movie (2002). In the film, Jonah is swallowed by a gargantuan whale.

## Suggested connections to legends

### Epic of Gilgamesh

Joseph Campbell suggests that the story of Jonah parallels a scene from the Epic of Gilgamesh, in which Gilgamesh obtains a plant from the bottom of the sea. In the Book of Jonah, a worm (in Hebrew tola'ath, "maggot") bites the shade-giving plant's root causing it to wither; whereas in the Epic of Gilgamesh, Gilgamesh ties stones to his feet and plucks his plant from the floor of the sea. Once he returns to the shore, the rejuvenating plant is eaten by a serpent.

### Jason (Greek mythology)

Campbell also noted several similarities between the story of Jonah and that of Jason in Greek mythology. The Greek rendering of the name Jonah is Jonas (Ἰωνᾶς), which differs from Jason (Ἰάσων) only in the order of sounds—both os are omegas suggesting that Jason may have been confused with Jonah. Gildas Hamel, drawing on the Book of Jonah and Greco-Roman sources—including Greek vases and the accounts of Apollonius of Rhodes, Gaius Valerius Flaccus and Orphic Argonautica—identifies a number of shared motifs, including the names of the heroes, the presence of a dove, the idea of "fleeing" like the wind and causing a storm, the attitude of the sailors, the presence of a sea-monster or dragon threatening the hero or swallowing him, and the form and the word used for the "gourd" (kikayon).

Hamel takes the view that it was the Hebrew author who reacted to and adapted this mythological material to communicate his own, quite different message.

## See also

- Aquanaut, a person who stays underwater for a long time
- Biblical and Quranic narratives
- Jonah on the Sistine Chapel ceiling
- Legends and the Quran
- Prophets of Islam
- Qisas Al-Anbiya

Quranic and Biblical prophet