Great Astronomers: Airy
Great Astronomers in Modern English
by Sir Robert S. Ball, 1895 (paraphrased by Leslie Noelani Laurio)
To view the table of contents for the rest of this book, click here.
Sir George Biddell Airy, 1801-1892
Multi-talented astronomer/engineer who helped establish the Prime Meridian at Greenwich, and measured the density of the earth.
In the chapter on Flamsteed, I explained how the famous Observatory on top of Greenwich Hill was founded. I also mentioned that Halley and Bradley were among the astronomers who succeeded Flamsteed as Astronomer Royal. But the subject of this chapter, George Biddell Airy, was responsible for a remarkable development at the Greenwich Observatory when he was its director. Due to his work, the Observatory was organized to such a state of perfection that it became a model for other observatories around the world. There is an excellent narrative of Airy's career in H. H. Turner's obituary of Airy which was published by the Royal Astronomy Society in 1892. I used that as a resource for this chapter. [page images are online starting here. Another copy here, pg 212.]
George Biddell Airy's ancestors came from Kentmore in Westmoreland [Westmoreland was absorbed into other counties, but seems to have been near Carlisle, England]. His father, William Airy, was from Lincolnshire, and his mother, Ann Biddell, was from Playford near Ipswich. William Airy had a government job that required him to move frequently. The family was living in Alnwick when George was born on July 27, 1801. As a boy, George went to school in Hereford and Colchester, but he didn't get much out of his schooling. What he loved were the holidays he spent on the farm at Playford. His Uncle Arthur was especially kind to him. George remembered the happy days of his early childhood all his life, and even bought a house in Playford when he was older as a retreat during the years of his exhausting career. In spite of his poor education, his uncle was impressed with his intellectual abilities and enrolled him at Cambridge University. He went to Trinity College as a sizar [serves other students in exchange for college expenses] in 1819. He did exceptionally well at mathematics and physical science and graduated as Senior Wrangler [the highest overall scores among math students] in 1823. In spite of the demands on his time while studying for his tripos [undergraduate exam], after his second term of residence, he was able to support himself by tutoring other students. A year after he graduated, he was elected to a Fellowship [graduate scholarship] at Trinity College.
Once he had an independent position, George Airy started on the scientific career that he pursued for the rest of his life. One of his earliest studies was on astigmatism, an eye condition that he himself was affected with. His research led him to suggest the use of eyeglasses with lenses specially shaped to counteract the light distortion caused by astigmatism. His research was thorough, and the principles he set down between 1825-1827 are still used by ophthalmologists to treat astigmatism.
In December 1826, George Airy was chosen as the Lucasan Professor of Mathematics at Cambridge, a position Isaac Newton had held 150 years earlier. Two years later he was chosen as Plumian Professor of Astronomy [named after Thomas Plume] at Cambridge. [This position allowed him to earn enough money to marry Richarda Smith. They met in 1824, and he wrote, "Our eyes met . . . and my fate was sealed . . . I felt irresistibly that we must be united." They were married in 1830.] The position probably appealed to him because it made him director of the new Observatory at Cambridge. Let's trace the history of this observatory.
In 1820, the more scientific-minded people at Cambridge decided they needed an observatory. They asked for donations and received £6,000 from University members and the public. The University itself added another £7,115. Administration regulations placed the new observatory under the management of the Plumian Professor, who would have two assistants. Their duties would be to make meridian observations of the sun, moon, and stars and print their observations every year. The observatory would also have an educational focus and be supplied with instruments to teach students to make astronomical observations.
The observatory building was finished in 1824, but when George Airy began his duties as Director, there was a lot of organizing to do. He plunged into his work so energetically that by the following year, he was able to publish the first volume of "Cambridge Astronomical Observations," in spite of having to do everything -- from making observations to revising the proof sheets-- by himself.
Those early volumes of the "Cambridge Astronomical Observations" contained the first explanations of George Airy's systematic methods of astronomical work which he developed later when he worked at the Greenwich Observatory. Those same methods were adopted in many other places. A budding astronomer will learn a lot by studying those volumes that George Airy wrote while he was Plumian Professor. He detailed very clearly the principles for doing meridian research.
Airy gradually added instruments to the observatory. [Airy's autobiography says that the Observatory only had one large instrument when he began his work there -- a 10-foot transit, which is a telescope on a moving wheel along the meridian.] A mural [or meridian] circle was added in 1832, and in the same year, Thomas Jones erected a small equatorial [telescope] mounted on a stone pier. This is the telescope that Airy used in his well-known series of observations of Jupiter's fourth satellite [the moon Callisto] which he used to determine Jupiter's mass. His memoir on the subject ["On the Mass of Jupiter as determined from the Observation of Elongations of the Fourth Satellite" published in Royal Astronomy Society Memoirs, April 1833] thoroughly explains his method of determining the weight of a planet by observing a satellite [moon] that orbits the planet. This is worthwhile reading for any student of astronomy. Airy's enthusiasm for astronomical research is apparent in his remarkable report about the progress of astronomy in the 1800's ["Report on the Progress of Astronomy During the Present Century," May 1832] that he read to the British Association at their second meeting. In his earliest years at Cambridge, his most well-known achievement had to do with theoretical astronomy that required advanced mathematics. This is a simplified idea of the subject:
The planet Venus is about the same size and weight as Earth, and its orbit lies within ours [Venus is between the earth and the sun, so Earth orbits around Venus, and Venus has a smaller orbit]. That means that Venus takes less time than Earth to circle around the sun -- but the ratios are the same, so Earth makes eight circles around the sun in the time it takes Venus to make almost thirteen. That means that if Earth and Venus are in line with the sun on one particular date, then eight years later, they will both be at the same place, in line with the sun. During those eight years, Earth will have made eight orbits around the sun, and Venus will have made thirteen orbits to get back to this same spot. Venus and Earth both have attraction forces [the pull of gravity] and they attract each other [as well as being attracted by the sun's more massive attraction force]. Because of Earth and Venus attracting each other, Earth is swayed out of its perfect elliptical orbit around the sun as Venus draws it closer to itself. Venus is also swayed out of its perfect orbit as Earth pulls it towards itself. Since the sun is so huge and heavy -- about 300,000 times as heavy as either Venus or Earth -- the amount that Venus and Earth are swayed out of their orbits is insignificant in their course around the sun. But under certain conditions, the pull of Earth and Venus towards each other is magnified and can make some interesting measurable patterns. Imagine if Venus and Earth had orbits that didn't relate to each other so simply -- if they weren't in line with the sun every eight years, but only very rarely. If that was the case, then the two planets pulling each other out of perfect orbit would happen much less often. But it happens every eight years -- that's pretty frequently, and it has a cumulative effect. The disturbance the two planets cause on each other is strongest when they're the closest to each other -- which is when they're in line with the sun every eight years. That means that every eight years, Earth's orbit is more strongly affected by Venus. Because of the numerical relationship between Venus and Earth [8 to 13], the disturbance on their orbits becomes significant enough to observe. George Airy decided to calculate the effects Venus's orbit would have on Earth due to the eight revolutions in the time it took Venus to make thirteen rotations. This is a complicated mathematical puzzle, but Airy was successful in solving it. He announced to the Royal Society that he had detected the influence that Venus asserted on Earth's orbit, and they awarded him the gold medal of the Royal Astronomical Society in 1832.
[There are computer graphic models that attempt to trace the beautiful geometric pattern made as Venus and Earth do their "dance" around the sun, such as this 40-second YouTube video. The effects in the video may be greatly exaggerated to make the pattern distinguishable. If you decide to look up more examples of these kinds of orbital patterns, be aware that this phenomenon is popular with astrology enthusiasts. If you'd like more astronomy computer animations to watch, this 9-min YouTube video provides a lot of technical details about the earth's tilt and orbit with terrific graphics.]
George Airy became so well-known for his scientific discoveries that the government awarded him a special pension. The Astronomer Royal in Greenwich, John Pond, resigned in 1835 [due to ill-health; he died a year later], and Airy was offered the position. The position he already had as Plumerian Professor in Cambridge required less work, which gave him more time to pursue his own research. As Astronomer Royal, he wouldn't have as much leisure time and the pay wasn't even as good. But he felt that it was his duty to agree to his government's request, so he went to Greenwich and became the new Astronomer Royal on October 1, 1835.
With his characteristic energy, he began organizing the way business was done at England's National Observatory. Astronomical observations almost always involve some kind of measurements that have to be reduced mathematically. For example, the astronomer might be measuring the exact time that a star crosses a line across his field of vision. Or he might be measuring an angle by looking at the degrees on a graduated circle through a microscope (!) while his telescope is pointed at a star positioned at a specific mark in his field of vision. In both of those cases, his notations will be a number, but it's rarely as simple as observing something and then writing down its measurement. Usually the observation gives one measurement, and then other influences have to be accounted for. If an observation were perfect, then its location as seen through the telescope would be its exact position. But it's never that straightforward. A telescope perfect enough to meet the demands of the astronomer could never be constructed. And the clock would have to be exactly correct, too, but that's rarely the case [not in 1895, apparently]. So the astronomer has to correct for errors, determining how much his telescope is off, and how far off his clock is. Then he has to calculate that as compared with what the measurement would have been if he had a perfect telescope and a perfect clock. There are other matters that have to be calculated into the measurement in order to reduce the figure from what was observed to what the actual position is. [Wikipedia says that reducing is "the transformation of numerical or alphabetical digital information derived empirically or experimentally into a corrected, ordered, and simplified form. The basic concept is the reduction of multitudinous amounts of data down to the meaningful parts."]
Calculating these reductions is intricate and monotonous work, so it's not unusual for recorded observations to accumulate in an observatory, while the tedious work of reducing these observations piles up, undone. When George Airy started working at the Greenwich Observatory, he found an enormous mass of observations. It was valuable data, but useless to astronomers until they were reduced. So Airy devoted himself to calculating the reductions of the work his predecessors had left behind. He created systematic methods to work out the reductions, and arranged the work so that all that was needed was careful attention to the numerical accuracy while doing the calculations. The Admiralty, who oversaw the Greenwich Observatory, encouraged him to use a large force of computers [mathematicians to help do the math? I don't think computers had been invented in 1895]. With his energy and organization, some extremely valuable planetary observations were reduced and published, and those were very important for astronomical research.
George Airy was a skilled and practical engineer as well as an optician, so he put his talents to use designing improved astronomical instruments to replace the outdated equipment he found in the observatory. Over the years, he completely transformed the instruments. He had a huge meridian circle constructed according to his own designs. He also designed the mounting for the equatorial telescope that was worked by a driving clock that he invented himself. [Telescopes were mounted on an equatorial -- a stand that can revolve to stay aligned with the equator -- supplied with a clock drive, which would be constructed with gears to automatically turn the equatorial mount so that the telescope could follow celestial objects as they moved in the sky. The result is that the telescope stays fixed in spite of the earth's rotation.] Under his meticulous management, the observatory became first rate. Every year, a board of visitors would inspect the observatory. Their chairman was the President of the Royal Society. The annual inspection was always the first Saturday in June. The Astronomer Royal would give the chairman a report explaining what he had accomplished during the past year, and including any requests for new instruments or applications to expand the work of observatory. Once the official inspection was done, the observatory would be opened for visitors, and hundreds of people would enjoy the privilege of seeing the national observatory on that day. In fact, these annual visits are still held on the first Saturday of June, and this day has come to be an opportunity for reunions of scientific men.
[George Airy installed a telescope in the Greenwich Observatory known as the Airy Transit Circle, which sits along the longitude line that was designation as the zero degree mark. In 1884, this spot was officially designated as the Prime Meridian of the world, the line that divides east from west and signifies the beginning of the new day. A transit telescope uses a clock drive and measures the exact time that a star crosses the Prime Meridian. This measurement is used for keeping precise time, and that precision time is used by ships for navigation.]
But George Airy's scientific work wasn't confined to the observatory. He was mostly interested in expeditions to observe eclipses from various locations, and in projects to measure the arc [curve] of the earth. He spent a lot of time collecting data brought from around the world for research about the earth's magnetic field. He investigated the transits of Venus [when Venus crosses the sun] in 1874 and 1882. Under his guidance, expeditions went out to make observations of the event from remote locations [such as Antarctica, and an island off Madagascar] in order to calculate how far away the sun was from the earth. Airy also studied phenomena related to the tides. He benefited his country by restoring the standards of length and weight that had been destroyed in the great fire at the House of Parliament in October, 1834. [Standardizing weights and measurements involved Henry Kater, Francis Baily, Richard Sheepshanks -- and a metal bar called "the Standard Yard" which was a casualty of a fire at the House of Commons. George Airy completed the work, which resulted in the Weights and Measures Act of 1855. "Airy points," which are precision measurements related to the sag of a beam, are named after him.] People sought his advice about all kinds of practical scientific matters, and he was always glad to help. At one time he researched the effects of iron-hulled ships causing magnetic deviation on compasses and made adjustments to the compass to compensate. Another time he gave advice about the best gauge for railways. [His advice was misunderstood and resulted in the Tay Bridge Disaster, which killed over 60 people when the bridge collapsed during a terrible storm while a train was crossing it.] One of his most useful developments was an electrical/galvanic device that could transmit the exact time by telegraph [1854]. The astronomers at Greenwich collaborated with the Post Office [who controlled the telegraph system] to transmit a signal from the observatory at Greenwich to nearby London at precisely ten o'clock every morning. Using a special apparatus [telegraph?], that signal would be transmitted automatically all over the country so that everyone would know it was ten o'clock at the same second [to synchronize their timekeepers by]. Connected to this system was a time ball on the top of a building in Deal [like the ball at Times Square on New Years Eve] that would drop every day at one o'clock for ships in the harbor to synchronize their chronometers. [The Deal Timeball Tower is 1 1/2 hours away from London on the harbor. You can see a picture of it on Wikipedia. There's a similar ball on top of the Greenwich Observatory that still drops at 1:00 -- "Greenwich Mean Time." Watch it drop on YouTube. View other timeballs around the world on Wikipedia.]
George Airy wrote extensively -- the "Catalogue of Scientific Memoirs" that were published by the Royal Society until 1873 mention forty-eight articles by him -- and that's in less than ten years of a long and active career! Sometimes non-scientific subjects engaged his attention. One time, for example, he wrote an interesting article about the Roman invasion of Britain, in which he focused on trying to determine the exact spot Caesar sailed from Gaul, and the exact place he landed in England. He was probably drawn to that topic as a result of his research of tides in the Straits of Dover. The general public is most familiar with him from the excellent lectures he gave about astronomy in the Ipswich Museum in 1848. [Chopin was in the UK Apr-Nov 1848 -- perhaps their paths crossed?] The lectures were published in a book that has gone through many editions. [Popular Astronomy: A Series of Lectures; online at archive.org]. His book explains how the most fundamental problems in astronomy should be approached.
Over his career, just about every honour and distinction that could be bestowed on a scientist was awarded to George Airy. In fact, he received awards outside the field of science. One was the Freedom of the City [much like the Key to the City] of London 1875 'in recognition of his diligent work in astronomy, and his well-known services in the advancement of practical science that has financially benefited the cause of trade and civilization.'
George Airy continued to work energetically until he was in his eighties. He finally resigned from the observatory in August 1881. Lady Airy, his wife, had died in 1875. Three sons and three daughters survived her. One daughter had married Dr. Routh of Cambridge, but Airy's other two daughters were his companions during his final years. He was in perfect health until he fell in late 1891 and suffered an internal injury and died in January 1892. He was buried near his wife's grave at St. Mary's Church in Playford, Suffolk.
[His autobiography is online at Project Gutenberg.]
by Sir Robert S. Ball, 1895 (paraphrased by Leslie Noelani Laurio)
To view the table of contents for the rest of this book, click here.
Sir George Biddell Airy, 1801-1892
Multi-talented astronomer/engineer who helped establish the Prime Meridian at Greenwich, and measured the density of the earth.
In the chapter on Flamsteed, I explained how the famous Observatory on top of Greenwich Hill was founded. I also mentioned that Halley and Bradley were among the astronomers who succeeded Flamsteed as Astronomer Royal. But the subject of this chapter, George Biddell Airy, was responsible for a remarkable development at the Greenwich Observatory when he was its director. Due to his work, the Observatory was organized to such a state of perfection that it became a model for other observatories around the world. There is an excellent narrative of Airy's career in H. H. Turner's obituary of Airy which was published by the Royal Astronomy Society in 1892. I used that as a resource for this chapter. [page images are online starting here. Another copy here, pg 212.]
George Biddell Airy's ancestors came from Kentmore in Westmoreland [Westmoreland was absorbed into other counties, but seems to have been near Carlisle, England]. His father, William Airy, was from Lincolnshire, and his mother, Ann Biddell, was from Playford near Ipswich. William Airy had a government job that required him to move frequently. The family was living in Alnwick when George was born on July 27, 1801. As a boy, George went to school in Hereford and Colchester, but he didn't get much out of his schooling. What he loved were the holidays he spent on the farm at Playford. His Uncle Arthur was especially kind to him. George remembered the happy days of his early childhood all his life, and even bought a house in Playford when he was older as a retreat during the years of his exhausting career. In spite of his poor education, his uncle was impressed with his intellectual abilities and enrolled him at Cambridge University. He went to Trinity College as a sizar [serves other students in exchange for college expenses] in 1819. He did exceptionally well at mathematics and physical science and graduated as Senior Wrangler [the highest overall scores among math students] in 1823. In spite of the demands on his time while studying for his tripos [undergraduate exam], after his second term of residence, he was able to support himself by tutoring other students. A year after he graduated, he was elected to a Fellowship [graduate scholarship] at Trinity College.
Once he had an independent position, George Airy started on the scientific career that he pursued for the rest of his life. One of his earliest studies was on astigmatism, an eye condition that he himself was affected with. His research led him to suggest the use of eyeglasses with lenses specially shaped to counteract the light distortion caused by astigmatism. His research was thorough, and the principles he set down between 1825-1827 are still used by ophthalmologists to treat astigmatism.
In December 1826, George Airy was chosen as the Lucasan Professor of Mathematics at Cambridge, a position Isaac Newton had held 150 years earlier. Two years later he was chosen as Plumian Professor of Astronomy [named after Thomas Plume] at Cambridge. [This position allowed him to earn enough money to marry Richarda Smith. They met in 1824, and he wrote, "Our eyes met . . . and my fate was sealed . . . I felt irresistibly that we must be united." They were married in 1830.] The position probably appealed to him because it made him director of the new Observatory at Cambridge. Let's trace the history of this observatory.
In 1820, the more scientific-minded people at Cambridge decided they needed an observatory. They asked for donations and received £6,000 from University members and the public. The University itself added another £7,115. Administration regulations placed the new observatory under the management of the Plumian Professor, who would have two assistants. Their duties would be to make meridian observations of the sun, moon, and stars and print their observations every year. The observatory would also have an educational focus and be supplied with instruments to teach students to make astronomical observations.
The observatory building was finished in 1824, but when George Airy began his duties as Director, there was a lot of organizing to do. He plunged into his work so energetically that by the following year, he was able to publish the first volume of "Cambridge Astronomical Observations," in spite of having to do everything -- from making observations to revising the proof sheets-- by himself.
Those early volumes of the "Cambridge Astronomical Observations" contained the first explanations of George Airy's systematic methods of astronomical work which he developed later when he worked at the Greenwich Observatory. Those same methods were adopted in many other places. A budding astronomer will learn a lot by studying those volumes that George Airy wrote while he was Plumian Professor. He detailed very clearly the principles for doing meridian research.
Airy gradually added instruments to the observatory. [Airy's autobiography says that the Observatory only had one large instrument when he began his work there -- a 10-foot transit, which is a telescope on a moving wheel along the meridian.] A mural [or meridian] circle was added in 1832, and in the same year, Thomas Jones erected a small equatorial [telescope] mounted on a stone pier. This is the telescope that Airy used in his well-known series of observations of Jupiter's fourth satellite [the moon Callisto] which he used to determine Jupiter's mass. His memoir on the subject ["On the Mass of Jupiter as determined from the Observation of Elongations of the Fourth Satellite" published in Royal Astronomy Society Memoirs, April 1833] thoroughly explains his method of determining the weight of a planet by observing a satellite [moon] that orbits the planet. This is worthwhile reading for any student of astronomy. Airy's enthusiasm for astronomical research is apparent in his remarkable report about the progress of astronomy in the 1800's ["Report on the Progress of Astronomy During the Present Century," May 1832] that he read to the British Association at their second meeting. In his earliest years at Cambridge, his most well-known achievement had to do with theoretical astronomy that required advanced mathematics. This is a simplified idea of the subject:
The planet Venus is about the same size and weight as Earth, and its orbit lies within ours [Venus is between the earth and the sun, so Earth orbits around Venus, and Venus has a smaller orbit]. That means that Venus takes less time than Earth to circle around the sun -- but the ratios are the same, so Earth makes eight circles around the sun in the time it takes Venus to make almost thirteen. That means that if Earth and Venus are in line with the sun on one particular date, then eight years later, they will both be at the same place, in line with the sun. During those eight years, Earth will have made eight orbits around the sun, and Venus will have made thirteen orbits to get back to this same spot. Venus and Earth both have attraction forces [the pull of gravity] and they attract each other [as well as being attracted by the sun's more massive attraction force]. Because of Earth and Venus attracting each other, Earth is swayed out of its perfect elliptical orbit around the sun as Venus draws it closer to itself. Venus is also swayed out of its perfect orbit as Earth pulls it towards itself. Since the sun is so huge and heavy -- about 300,000 times as heavy as either Venus or Earth -- the amount that Venus and Earth are swayed out of their orbits is insignificant in their course around the sun. But under certain conditions, the pull of Earth and Venus towards each other is magnified and can make some interesting measurable patterns. Imagine if Venus and Earth had orbits that didn't relate to each other so simply -- if they weren't in line with the sun every eight years, but only very rarely. If that was the case, then the two planets pulling each other out of perfect orbit would happen much less often. But it happens every eight years -- that's pretty frequently, and it has a cumulative effect. The disturbance the two planets cause on each other is strongest when they're the closest to each other -- which is when they're in line with the sun every eight years. That means that every eight years, Earth's orbit is more strongly affected by Venus. Because of the numerical relationship between Venus and Earth [8 to 13], the disturbance on their orbits becomes significant enough to observe. George Airy decided to calculate the effects Venus's orbit would have on Earth due to the eight revolutions in the time it took Venus to make thirteen rotations. This is a complicated mathematical puzzle, but Airy was successful in solving it. He announced to the Royal Society that he had detected the influence that Venus asserted on Earth's orbit, and they awarded him the gold medal of the Royal Astronomical Society in 1832.
[There are computer graphic models that attempt to trace the beautiful geometric pattern made as Venus and Earth do their "dance" around the sun, such as this 40-second YouTube video. The effects in the video may be greatly exaggerated to make the pattern distinguishable. If you decide to look up more examples of these kinds of orbital patterns, be aware that this phenomenon is popular with astrology enthusiasts. If you'd like more astronomy computer animations to watch, this 9-min YouTube video provides a lot of technical details about the earth's tilt and orbit with terrific graphics.]
George Airy became so well-known for his scientific discoveries that the government awarded him a special pension. The Astronomer Royal in Greenwich, John Pond, resigned in 1835 [due to ill-health; he died a year later], and Airy was offered the position. The position he already had as Plumerian Professor in Cambridge required less work, which gave him more time to pursue his own research. As Astronomer Royal, he wouldn't have as much leisure time and the pay wasn't even as good. But he felt that it was his duty to agree to his government's request, so he went to Greenwich and became the new Astronomer Royal on October 1, 1835.
With his characteristic energy, he began organizing the way business was done at England's National Observatory. Astronomical observations almost always involve some kind of measurements that have to be reduced mathematically. For example, the astronomer might be measuring the exact time that a star crosses a line across his field of vision. Or he might be measuring an angle by looking at the degrees on a graduated circle through a microscope (!) while his telescope is pointed at a star positioned at a specific mark in his field of vision. In both of those cases, his notations will be a number, but it's rarely as simple as observing something and then writing down its measurement. Usually the observation gives one measurement, and then other influences have to be accounted for. If an observation were perfect, then its location as seen through the telescope would be its exact position. But it's never that straightforward. A telescope perfect enough to meet the demands of the astronomer could never be constructed. And the clock would have to be exactly correct, too, but that's rarely the case [not in 1895, apparently]. So the astronomer has to correct for errors, determining how much his telescope is off, and how far off his clock is. Then he has to calculate that as compared with what the measurement would have been if he had a perfect telescope and a perfect clock. There are other matters that have to be calculated into the measurement in order to reduce the figure from what was observed to what the actual position is. [Wikipedia says that reducing is "the transformation of numerical or alphabetical digital information derived empirically or experimentally into a corrected, ordered, and simplified form. The basic concept is the reduction of multitudinous amounts of data down to the meaningful parts."]
Calculating these reductions is intricate and monotonous work, so it's not unusual for recorded observations to accumulate in an observatory, while the tedious work of reducing these observations piles up, undone. When George Airy started working at the Greenwich Observatory, he found an enormous mass of observations. It was valuable data, but useless to astronomers until they were reduced. So Airy devoted himself to calculating the reductions of the work his predecessors had left behind. He created systematic methods to work out the reductions, and arranged the work so that all that was needed was careful attention to the numerical accuracy while doing the calculations. The Admiralty, who oversaw the Greenwich Observatory, encouraged him to use a large force of computers [mathematicians to help do the math? I don't think computers had been invented in 1895]. With his energy and organization, some extremely valuable planetary observations were reduced and published, and those were very important for astronomical research.
George Airy was a skilled and practical engineer as well as an optician, so he put his talents to use designing improved astronomical instruments to replace the outdated equipment he found in the observatory. Over the years, he completely transformed the instruments. He had a huge meridian circle constructed according to his own designs. He also designed the mounting for the equatorial telescope that was worked by a driving clock that he invented himself. [Telescopes were mounted on an equatorial -- a stand that can revolve to stay aligned with the equator -- supplied with a clock drive, which would be constructed with gears to automatically turn the equatorial mount so that the telescope could follow celestial objects as they moved in the sky. The result is that the telescope stays fixed in spite of the earth's rotation.] Under his meticulous management, the observatory became first rate. Every year, a board of visitors would inspect the observatory. Their chairman was the President of the Royal Society. The annual inspection was always the first Saturday in June. The Astronomer Royal would give the chairman a report explaining what he had accomplished during the past year, and including any requests for new instruments or applications to expand the work of observatory. Once the official inspection was done, the observatory would be opened for visitors, and hundreds of people would enjoy the privilege of seeing the national observatory on that day. In fact, these annual visits are still held on the first Saturday of June, and this day has come to be an opportunity for reunions of scientific men.
[George Airy installed a telescope in the Greenwich Observatory known as the Airy Transit Circle, which sits along the longitude line that was designation as the zero degree mark. In 1884, this spot was officially designated as the Prime Meridian of the world, the line that divides east from west and signifies the beginning of the new day. A transit telescope uses a clock drive and measures the exact time that a star crosses the Prime Meridian. This measurement is used for keeping precise time, and that precision time is used by ships for navigation.]
But George Airy's scientific work wasn't confined to the observatory. He was mostly interested in expeditions to observe eclipses from various locations, and in projects to measure the arc [curve] of the earth. He spent a lot of time collecting data brought from around the world for research about the earth's magnetic field. He investigated the transits of Venus [when Venus crosses the sun] in 1874 and 1882. Under his guidance, expeditions went out to make observations of the event from remote locations [such as Antarctica, and an island off Madagascar] in order to calculate how far away the sun was from the earth. Airy also studied phenomena related to the tides. He benefited his country by restoring the standards of length and weight that had been destroyed in the great fire at the House of Parliament in October, 1834. [Standardizing weights and measurements involved Henry Kater, Francis Baily, Richard Sheepshanks -- and a metal bar called "the Standard Yard" which was a casualty of a fire at the House of Commons. George Airy completed the work, which resulted in the Weights and Measures Act of 1855. "Airy points," which are precision measurements related to the sag of a beam, are named after him.] People sought his advice about all kinds of practical scientific matters, and he was always glad to help. At one time he researched the effects of iron-hulled ships causing magnetic deviation on compasses and made adjustments to the compass to compensate. Another time he gave advice about the best gauge for railways. [His advice was misunderstood and resulted in the Tay Bridge Disaster, which killed over 60 people when the bridge collapsed during a terrible storm while a train was crossing it.] One of his most useful developments was an electrical/galvanic device that could transmit the exact time by telegraph [1854]. The astronomers at Greenwich collaborated with the Post Office [who controlled the telegraph system] to transmit a signal from the observatory at Greenwich to nearby London at precisely ten o'clock every morning. Using a special apparatus [telegraph?], that signal would be transmitted automatically all over the country so that everyone would know it was ten o'clock at the same second [to synchronize their timekeepers by]. Connected to this system was a time ball on the top of a building in Deal [like the ball at Times Square on New Years Eve] that would drop every day at one o'clock for ships in the harbor to synchronize their chronometers. [The Deal Timeball Tower is 1 1/2 hours away from London on the harbor. You can see a picture of it on Wikipedia. There's a similar ball on top of the Greenwich Observatory that still drops at 1:00 -- "Greenwich Mean Time." Watch it drop on YouTube. View other timeballs around the world on Wikipedia.]
George Airy wrote extensively -- the "Catalogue of Scientific Memoirs" that were published by the Royal Society until 1873 mention forty-eight articles by him -- and that's in less than ten years of a long and active career! Sometimes non-scientific subjects engaged his attention. One time, for example, he wrote an interesting article about the Roman invasion of Britain, in which he focused on trying to determine the exact spot Caesar sailed from Gaul, and the exact place he landed in England. He was probably drawn to that topic as a result of his research of tides in the Straits of Dover. The general public is most familiar with him from the excellent lectures he gave about astronomy in the Ipswich Museum in 1848. [Chopin was in the UK Apr-Nov 1848 -- perhaps their paths crossed?] The lectures were published in a book that has gone through many editions. [Popular Astronomy: A Series of Lectures; online at archive.org]. His book explains how the most fundamental problems in astronomy should be approached.
Over his career, just about every honour and distinction that could be bestowed on a scientist was awarded to George Airy. In fact, he received awards outside the field of science. One was the Freedom of the City [much like the Key to the City] of London 1875 'in recognition of his diligent work in astronomy, and his well-known services in the advancement of practical science that has financially benefited the cause of trade and civilization.'
George Airy continued to work energetically until he was in his eighties. He finally resigned from the observatory in August 1881. Lady Airy, his wife, had died in 1875. Three sons and three daughters survived her. One daughter had married Dr. Routh of Cambridge, but Airy's other two daughters were his companions during his final years. He was in perfect health until he fell in late 1891 and suffered an internal injury and died in January 1892. He was buried near his wife's grave at St. Mary's Church in Playford, Suffolk.
[His autobiography is online at Project Gutenberg.]
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