Tuesday, 2 October 2012

The Magnetic Meditations of the Scientific Sabine

                     If Sabine Baring-Gould was exceptional, it may well be that he was seeking to emulate his uncle Edward Sabine (after whom he was named). Edward was born to Anglo-Irish parents at Dublin in 1788, and Sarah, his mother, died within a month of his birth. He was educated at Marlow and the Royal Military Academy, Woolwich, and entered the military in 1803, at fifteen, as a second lieutenant. He fought, with distinction, in the Anglo-American War of 1812-15, when he commanded the batteries at the Siege of Fort Erie (1814) and was twice mentioned favourably in despatches. 

Edward Sabine

In 1816, he returned to England and dedicated the rest of his life to scientific researches. He was elected a Fellow of the Royal Society in 1818, and on the recommendation of the president and council he was appointed as astronomer on the Isabella, which sailed to the Arctic under command of Commander (later Sir) John Ross. The primary aim of the voyage was to discover a Northwest passage that would enable ships to sail over the north of the Americas, thereby linking the Atlantic and Pacific oceans (and thus avoiding a voyage around the treacherous southern Cape Horn). 

J Ross - Lancaster Sound - August 31 1818

The voyage was considered to have been a failure when Ross returned early after finding Lancaster Sound blocked by sea ice, despite objections from the other officers (including Sabine and William Parry, the second in command), and a public row ensued after their return. 

Sabine's Gull

Sabine recorded twenty-four species of birds at Greenland, including the Fork Tailed Gull Larus sabini (named for him) and his paper was well received by the Linnean Society in 1819. 

Edward Sabine- A Memoir on the Birds of Greenland - 1818

A second voyage, under the command of Parry, with Sabine and his elder brother, Joseph, aboard the Hecla and the Griper sailed in May 1819, and although this voyage also failed to find a Northwest passage, it did set a new ‘furthest West’ record which stood for decades. Sabine made numerous magnetic measurements and collected invaluable scientific data, for which he was awarded the Copley Medal by the Royal Society in 1821. 

E Sabine - Magnetical Log from 1st Ross expedition 1818

Sabine undertook further work on magnetism, continuing experiments he had made on his first polar voyage, with the seconds pendulum (a pendulum which swings through its complete arc in two seconds, one second in one direction, another second in the other), at standard gravity, with a length of 0.994 m (39.1 inches) – a length that was once the standard metre. The length of the pendulum varies at different latitudes and by use of extremely precise instrumentation, Sabine was able to ascertain the true shape of the Earth (the planet is not a perfect sphere – it is an oblate spheroid, flattened slightly at the poles). Sabine travelled half the Earth for eighteen months to take his measurements, onboard the Griper now under the command of Captain Clavering; Sabine later had an island off the east coast of Greenland named after him, in honour of his work. 

Sabine Island

He also worked on the problem of longitude, hoping to be able to calculate it by measuring the dip of a compass needle, but the improved chronometers made available through the work of John Harrison made the question largely irrelevant. In 1828, the Admiralty abolished the Board of Longitude, but they retained three scientific advisers – Michael Faraday, Thomas Young and Sabine; Charles Babbage objected in the strongest terms to Sabine’s appointment, largely because he refused to accept the scientific credentials of the Royal Society. To his credit, Sabine remained aloof and refused to be drawn into the controversy. 

Although the Duke of Wellington had exempted Sabine from military matters on condition that he continued to concentrate on his scientific endeavours, a crisis in Ireland caused him to be recalled and sent to the land of his birth, where he managed to maintain his studies and in 1835, completed a systematic magnetic survey of Ireland, followed by the same in 1836 of Scotland, and England the following year. Sabine then approached the Government with a proposal to carry out a similar survey worldwide, establishing magnetic stations across the globe, as part of an investigation of why there were alterations in the Earth’s magnetic field (a phenomena which caused variations in compass readings). 

Terrestrial Magnetism

This ‘Magnetic Crusade’ opened observatories across the British Empire and other countries were invited to participate, and Sabine was appointed as superintendent of the project, correlating the vast amounts of data and presenting the findings. In 1840, he commenced publishing a series of Contributions to Terrestrial Magnetism to the Philosophical Transactions of the Royal Society, which continued for the next thirty-six years, and resulted in the most accurate magnetic survey of the planet possible at the time. It was, and is, a remarkable achievement. 

Edward Sabine

In 1869, he was knighted and in 1877, he retired from the army on full pay, with the rank of General. In 1826, he had married Elizabeth Juliana Leeves, a remarkable woman in her own right, who, between 1849 and 1858, published a four-volume translation of Alexander von Humboldt’s Kosmos, a textbook on geophysics. She died in 1879 and General Sir Edward Sabine died in 1883. 

Edward Sabine

In addition to Sabine’s Gull and Sabine Insel, a tree Pinus sabineana and a crater on the Moon are named after him. Sabine Crater lies immediately adjacent to the landing site of the first manned moon landing of Apollo XI in July 1969.

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