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John Gwyn Jeffreys

John Gwyn Jeffreys is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand John Gwyn Jeffreys rather than just read about it. In short: John Gwyn Jeffreys FRS (18 January 1809 – 21 January 1885) was a British conchologist and malacologist. Biography John Gwyn Jeffreys was born on 18 January 1809, at Swansea, Wales.

John Gwyn Jeffreys — main illustration
John Gwyn Jeffreys — illustration

Key takeaways

  • John Gwyn Jeffreys belongs to earth science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect John Gwyn Jeffreys to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of John Gwyn Jeffreys from memory before moving on to harder problems.

Reference excerpt

John Gwyn Jeffreys FRS (18 January 1809 – 21 January 1885) was a British conchologist and malacologist.

Biography John Gwyn Jeffreys was born on 18 January 1809, at Swansea, Wales. He was the eldest son of J. Jeffreys of Fynone, Glamorgan. Jeffreys was educated in Swansea at the Bishop Gore School (Swansea Grammar School). From the age of seventeen, he was an apprentice to one of the principal solicitors of Swansea, before going to London, where he qualified as a barrister in 1838. Jeffreys worked as a solicitor in Swansea until 1856, when he was called to the bar in London. But his greater passion was for conchology. He was not satisfied simply to form a collection, but was interested in all aspects of the biology of molluscs. On 2 April 1840 he became a Fellow of the Royal Society. On 21 June that year he married Ann Nevill at Llangennech. They had a son and four daughters; and were the grandparents of the physicist, Henry Gwyn Jeffreys Moseley. In 1866 Jeffreys retired from the law, and continued a series of dredging operations he started in 1861 aboard the yacht, Osprey, which he later purchased from his brother-in-law. Accompanied by other specialists in marine life such as Charles William Peach (1800–1886), the Reverend Alfred Merle Norman (1831–1918), George Barlee (1794–1861) and Edward Waller (1803–1873), he dredged the seas around the Shetland Islands, the west of Scotland, the English Channel and the Irish Sea. He also went on expeditions to Norway. He went on to take part in several deepsea expeditions as scientific leader – the Porcupine expeditions in 1869 and 1870, the Valorous expedition to Greenland in 1875, and the French Travailleur expedition in 1880. In or shortly after 1866 he moved from London to Ware in Hertfordshire, where he bought the Greyfriars Priory, and made it a meeting-place for many British and foreign artists. He served as Justice of the Peace for Glamorgan, Brecon and Hertfordshire, and was appointed High Sheriff of the latter in 1877. He was Treasurer of the Linnean Society of London and Geological Society of London for many years. Jeffreys was also a member of the British Association for the Advancement of Science. After the death of his wife in 1881, Jeffreys moved to Kensington, and he died there 24 January 1885.

His principal work was his well known 'British Conchology,' in five volumes, the best on the subject. He was throughout his life a most indefatigable worker, and at time of his death was still actively engaged upon the description of the deep-sea mollusca dredged by the Lightning and the Porcupine expeditions. He read the ninth of his series of papers on this subject at the Zoological Society's meeting four days before his death. It ranged from the Ianthinidæ to the Cerithiopsidæ, including seventy-five species, of which twenty-three were new, including one new genus. Among the species first scientifically described by Jeffreys are Rissoella opalina (1848), Cima minima (1858), and Cheirodonta pallescens (1867). His collection of shells and specimens was bought by William Healey Dall (1845–1927) for the Smithsonian Institution in the United States of America, and was partly donated to the National Museum of Natural History, Washington, D.C.

Bibliography Jeffreys was the author of a number of books and articles on conchology and the mechanics of sea dredging. Of particular note was British Conchology, or an account of the Mollusca which now inhabit the British Isles and the surrounding seas (five volumes, 1862 – 1865), illustrated by George Brettingham Sowerby II. A complete list of scientific papers by John Gwyn Jeffreys including reviews is online here [1].

References

Sources Carpenter, W.B. (1885). John Gwyn Jeffreys, Obituary. Proceedings of the Royal Society of London 38: xiv–xviii Darwin, Charles; Burkhardt, Frederick (1999). The Correspondence of Charles Darwin. Vol. 11. Cambridge: Cambridge University Press. p. 833. ISBN 9780521590334. Hans G. Hansson. "Biographical Etymology of Marine Organism Names (BEMON)". University of Gothenburg. Archived from the original on 16 May 2011. Parts of this article were translated from the French Wikipedia

External links Works by or about John Gwyn Jeffreys at the Internet Archive

Illustrations

John Gwyn Jeffreys illustration

Worked examples

Example 1 — a first encounter with John Gwyn Jeffreys

Start with the simplest possible case. Write down what John Gwyn Jeffreys claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to John Gwyn Jeffreys before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about John Gwyn Jeffreys ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of John Gwyn Jeffreys

In research
John Gwyn Jeffreys appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses John Gwyn Jeffreys in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
John Gwyn Jeffreys is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1809 births, 1885 deaths, British conchologists, so understanding it makes those chapters shorter.
In everyday life
Look for John Gwyn Jeffreys outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study John Gwyn Jeffreys in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what John Gwyn Jeffreys means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain John Gwyn Jeffreys out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John Gwyn Jeffreys in simple terms?

John Gwyn Jeffreys FRS (18 January 1809 – 21 January 1885) was a British conchologist and malacologist. Biography John Gwyn Jeffreys was born on 18 January 1809, at Swansea, Wales.

Why does John Gwyn Jeffreys matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study John Gwyn Jeffreys?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on John Gwyn Jeffreys.

Tags

  • 1809 births
  • 1885 deaths
  • British conchologists
  • British fellows of the Royal Society
  • British malacologists
  • Fellows of the Geological Society of London
  • Fellows of the Linnean Society of London
  • High sheriffs of Hertfordshire
  • People educated at Bishop Gore School
  • People from Swansea
  • Welsh barristers

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