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Dr Allan Chapman, Wadham College, Oxford, on 21 November 2003
Joint Meeting with The Institute of Physics and The William Herschel Society
George Airy was born at Alnwick, Northumberland, on 27 July 1801 and died at the age of 92. Before his appointment all Astronomers Royal had been rich amateurs who paid for their own equipment and needed no salary. "Their income came from benefices, inheritance, their wife, the law or brewing." Airy informed the authorities on his appointment in 1835 that he depended on his salary, initially £800/yr; he also administered the Observatory strictly so that time and money were accounted for carefully - a major change.
Airy's attitude may have derived from the disaster to his family when he was 13: his father, a custom & excise tax collector was dismissed from his job and the family became impoverished. The reason for his dismisssal is not known. George went to live with his uncle, William Biddell, a prosperous land-owner with a magnificent house in Playford, Essex. He got a scholarship to Ipswich Grammar School and in 1820 went to Cambridge with two scholarships for Trinity College. He was a brilliant mathematician and classical scholar who, in 1823, got twice the marks in the final examinations of the man who came second. He then became a Fellow of Trinity College and a maths tutor who organised the first reading parties for undergraduates in the Lake District and South Wales.
He became an astronomer through mathematics, not observation. Calculation of right ascension and declination to very high levels of accuracy were his first interest. He was taught astronomy by Mr South, an eminent surgeon, who was a keen amateur astronomer. John Herschel, who was 9 years older, was also with South and became a friend. Airy became Lucasian Professor and Plumian Professor at Cambridge and in 1828 was appointed Director of the Cambridge University Observatory. This appointment enabled him to meet the requirement of Miss Smith's father that he should have an income of £500 / yr before he married her; they subsequently had nine children, six of whom survived to adulthood. This may explains why Airy was uninterested in clubs and social events, attending only the Royal Astronomical Society's meeting.
In 1835 he was appointed Astronomer Royal, which he found had been badly administered by his predecessor who was only interested in observing through telescopes. Airy sacked the First Assistant and appointed a highly qualified Cambridge MA, a policy continued until Greenwich Observatory closed. There were a few Assistants of similar quality, Warrant Assistants who came as apprentices, and Juniors as calculators.
Their main task was to provide information for the Admiralty for navigation, but this included work on the effect of the iron hull of the modern ships and of the motion of the engine on the ship's compass; checking chronometers for accuracy; and the signalling of accurate time to ships in port around the coast.
Airy was a practical engineer who devised instruments and mounting for telescopes and supervised their construction. He virtually re-built all the instruments in the Observatory. This led to him being consulted about the gauge of railway lines, deciding between the 'Brunel' 7 foot and the 'standard' 4 ft-8½ in distance; he selected the latter for general use. He then got involved with railway signalling using electricity.
This led him to adopt electricity for signalling the time from Greenwich to ports around the country so that the 'falling ball' indicators which navigators aboard ships watched at 1 o'clock every day could all fall at the same instant. The first such electric signal was sent from Greenwich to Lewisham Station in 1852.
Airy became involved in two disputes that wrecked friendships, one with South and another with Adams. In both cases his insistence on accuracy and precision caused problems.
South had ordered a new telescope from Troughton in 1829 but refused to pay for it saying it did not met his requirements. Troughton went to law and Airy supported him; he considered South expected more than could be provided by the techniques available.
Adams had investigated a suggestion made by Airy when he was at Cambridge in 1828 that there might be another one or more planets disturbing the orbit of Uranus, unless Newton's Laws did not apply at that distance from the Sun. By 1845 Adams had made some calculations which Airy discounted as insufficiently accurate and not published for peer review. Adams called unannounced several times and was not admitted because it was inconvenient to Airy or he was away, and Adams took offence. This became known as The Neptune Controversy. Adams wanted Greenwich to search the sky for Neptune. Airy would never have agreed to do so: "Government equipment is not to be used for private observations" being his argument - a further example of his strict policy at the Observatory.
Airy retired as Astronomer Royal in 1881 having rejected three offers of knighthoods in 1834, 1847 and 1863 because he considered his income was inadequate to maintain the life style such an honour would require and he would only become an object of derision. In 1871 he was finally awarded the Order of the Bath.
The compensation of the compass for the iron in the hull and engine was achieved by fitting bar magnets at certain place around the vessel that resulted in the compass being in a magnetically neutral area. Wooden vessels had similar problems from their numerous iron cannon.
It is not known whether he kept in contact with his father whilst living with his uncle. His father died in 1838.
The leap-second was not introduced in Airy's time; it required an atomic clock that was not related to the rotation of the Earth to show that such a correction was necessary.
Airy was in contact with the Royal family, especially Prince Albert, at various times.
He was completely wrong in his controversy with William Whewell about tides.