This article's lead section may be too short to adequately summarize the key points.(September 2024) |
Sir James Dewar | |
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Born | Kincardine-on-Forth, Scotland | 20 September 1842
Died | 27 March 1923 80) London, England | (aged
Alma mater | University of Edinburgh |
Known for | |
Awards |
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Scientific career | |
Fields | Physics, chemistry |
Institutions | |
Doctoral advisor | Lord Playfair |
Sir James Dewar FRS FRSE ( /djuːər/ DEW-ər; [1] 20 September 1842 – 27 March 1923) was a Scottish chemist and physicist. He is best known for his invention of the vacuum flask, which he used in conjunction with research into the liquefaction of gases. He also studied atomic and molecular spectroscopy, working in these fields for more than 25 years. Dewar was nominated for the Nobel Prize 8 times — 5 times in Physics and 3 times in Chemistry — but he was never so honoured. [2]
James Dewar was born in Kincardine, Perthshire (now in Fife) in 1842, the youngest of six boys of Ann Dewar and Thomas Dewar, a vintner. [3] He was educated at Kincardine Parish School and then Dollar Academy. His parents died when he was 15. He attended the University of Edinburgh where he studied chemistry under Lyon Playfair (later Baron Playfair), becoming Playfair's personal assistant. Dewar also studied under August Kekulé at Ghent.
In 1875, Dewar was elected Jacksonian professor of natural experimental philosophy at the University of Cambridge, becoming a member of Peterhouse. [4] He became a member of the Royal Institution and later, in 1877, replaced Dr John Hall Gladstone in the role of Fullerian Professor of Chemistry. Dewar was also the President of the Chemical Society in 1897 and the British Association for the Advancement of Science in 1902, as well as serving on the Royal Commission established to examine London's water supply from 1893 to 1894 and the Committee on Explosives. While serving on the Committee on Explosives, he and Frederick Augustus Abel developed cordite, a smokeless gunpowder alternative.
In 1867 Dewar described several chemical formulas for benzene, which were published in 1869. [5] One of the formulae, which does not represent benzene correctly and was not advocated by Dewar, is sometimes still called Dewar benzene. [6] In 1869 he was elected a Fellow of the Royal Society of Edinburgh, his proposer being his former mentor, Lyon Playfair. [3]
His scientific work covers a wide field – his earlier papers cover topics including organic chemistry, hydrogen and its physical constants, high-temperature research, the temperature of the Sun and of the electric spark, spectrophotometry, and the chemistry of the electric arc.
With Professor J. G. McKendrick, of the University of Glasgow, he investigated the physiological action of light and examined the changes that take place in the electrical condition of the retina under its influence. With Professor G. D. Liveing, one of his colleagues at the University of Cambridge, he began in 1878 a long series of spectroscopic observations, the later of which were devoted to the spectroscopic examination of various gaseous elements separated from atmospheric air by the aid of low temperatures. He was joined by Professor J. A. Fleming, of University College London, in the investigation of the electrical behaviour of substances cooled to very low temperatures.
His name is most widely known in connection with his work on the liquefaction of the so-called permanent gases and his researches at temperatures approaching absolute zero. [7] His interest in this branch of physics and chemistry dates back at least as far as 1874, when he discussed the "Latent Heat of Liquid Gases" before the British Association. In 1878, he devoted a Friday evening lecture at the Royal Institution to the then-recent work of Louis Paul Cailletet and Raoul Pictet, and exhibited for the first time in Great Britain the working of the Cailletet apparatus. Six years later, again at the Royal Institution, he described the researches of Zygmunt Florenty Wróblewski and Karol Olszewski, and illustrated for the first time in public the liquefaction of oxygen and air. Soon afterward, he built a machine from which the liquefied gas could be drawn off through a valve for use as a cooling agent, before using the liquid oxygen in research work related to meteorites; about the same time, he also obtained oxygen in the solid state.
By 1891, he had designed and built, at the Royal Institution, machinery which yielded liquid oxygen in industrial quantities, and towards the end of that year, he showed that both liquid oxygen and liquid ozone are strongly attracted by a magnet. About 1892, the idea occurred to him of using vacuum-jacketed vessels for the storage of liquid gases – the Dewar flask (otherwise known as a Thermos or vacuum flask) – the invention for which he became most famous. The vacuum flask was so efficient at keeping heat out, it was found possible to preserve the liquids for comparatively long periods, making an examination of their optical properties possible. Dewar did not profit from the widespread adoption of his vacuum flask – he lost a court case against Thermos concerning the patent for his invention. While Dewar was recognised as the inventor, because he did not patent his invention, there was no way to prevent Thermos from using his design. [8]
He next experimented with a high-pressure hydrogen jet by which low temperatures were realised through the Joule–Thomson effect, and the successful results he obtained led him to build at the Royal Institution a large regenerative cooling refrigerating machine. Using this machine in 1898, liquid hydrogen was collected for the first time, solid hydrogen following in 1899. He tried to liquefy the last remaining gas, helium, which condenses into a liquid at −268.9 °C, but owing to a number of factors, including a short supply of helium, Dewar was preceded by Heike Kamerlingh Onnes as the first person to produce liquid helium, in 1908. Onnes would later be awarded the Nobel Prize in Physics for his research into the properties of matter at low temperatures – Dewar was nominated several times, but never succeeded in winning the Nobel Prize. [8]
In 1905, he began to investigate the gas-absorbing powers of charcoal when cooled to low temperatures and applied his research to the creation of high vacuum, which was used for further experiments in atomic physics. Dewar continued his research work into the properties of elements at low temperatures, specifically low-temperature calorimetry, until the outbreak of World War I. The Royal Institution laboratories lost a number of staff to the war effort, both in fighting and scientific roles, and after the war, Dewar had little interest in restarting the serious research work that went on before the war. Shortages of scholars necessarily compounded the problems. His research during and after the war mainly involved investigating surface tension in soap bubbles, rather than further work into the properties of matter at low temperatures.
Dewar died on 27 March 1923 aged 80 and was cremated at Golders Green Crematorium in London. An urn with his ashes still resides there.
He married Helen Rose Banks in 1871. They had no children. Helen was sister-in-law to both Charles Dickson, Lord Dickson and James Douglas Hamilton Dickson. [3]
Dewar's nephew, Dr Thomas William Dewar FRSE, was an amateur artist, who painted a portrait of Sir James Dewar. [9] He is presumably also the same Thomas William Dewar who was mentioned as executor in James Dewar's will, ultimately replaced "unopposed" by Dewar's wife. [10]
Dewar was invited to deliver several Royal Institution Christmas Lectures:
Whilst Dewar was never recognised by the Swedish Academy, he was recognised by many other institutions both before and after his death, in Britain and overseas. The Royal Society elected him a Fellow of the Royal Society in June 1877 and bestowed their Rumford (1894), Davy (1909), and Copley Medal (1916) medals upon him for his work, as well as inviting him to deliver their Bakerian Lecture in 1901. [11] In 1899, he became the first recipient of the Hodgkins gold medal of the Smithsonian Institution, Washington, DC, for his contributions to knowledge of the nature and properties of atmospheric air. That same year, he was elected to the American Philosophical Society. [12] He was elected to the United States National Academy of Sciences in 1907. [13]
He was President of the Society of Chemical Industry from 1887-88. [14]
In 1904, he was the first British subject to receive the Lavoisier Medal of the French Academy of Sciences, and in 1906, he was the first to be awarded the Matteucci Medal of the Italian Society of Sciences. He was knighted in 1904 and awarded the Gunning Victoria Jubilee Prize for 1900–1904 by the Royal Society of Edinburgh, and in 1908, he was awarded the Albert Medal of The Society of Arts. A lunar crater was named in his honour.
A street within the Kings Buildings complex of the University of Edinburgh was named in memory of Dewar in the early 21st century.
Dewar's irascibility was legendary. Rowlinson (2012) called him "ruthless", particularly with his colleague Siegfried Ruhemann. [15]
Collected Papers on Spectroscopy., G. D. Living and J. Dewar, Cambridge University Press, 1915
In physics, cryogenics is the production and behaviour of materials at very low temperatures.
Helium is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements, and it does not have a melting point at standard pressures. It is the second-lightest and second most abundant element in the observable universe, after hydrogen. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and Jupiter, because of the very high nuclear binding energy of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. Large amounts of new helium are created by nuclear fusion of hydrogen in stars.
Neon is a chemical element; it has the symbol Ne and atomic number 10. It is the second noble gas in the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately two-thirds the density of air.
Oxygen is a chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, and the third-most abundant element in the universe after hydrogen and helium.
Liquid hydrogen (H2(l)) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.
The following is a timeline of low-temperature technology and cryogenic technology. It also lists important milestones in thermometry, thermodynamics, statistical physics and calorimetry, that were crucial in development of low temperature systems.
A vacuum flask is an insulating storage vessel that slows the speed at which its contents change in temperature. It greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings by trying to be as adiabatic as possible. Invented by James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which significantly reduces heat transfer by conduction or convection. When used to hold cold liquids, this also virtually eliminates condensation on the outside of the flask.
Liquid nitrogen (LN2) is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about −196 °C (−321 °F; 77 K). It is produced industrially by fractional distillation of liquid air. It is a colorless, mobile liquid whose viscosity is about one-tenth that of acetone (i.e. roughly one-thirtieth that of water at room temperature). Liquid nitrogen is widely used as a coolant.
Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures. Liquid helium may show superfluidity.
Thomas Andrews FRS FRSE was an Irish chemist and physicist who did important work on phase transitions between gases and liquids. He was a longtime professor of chemistry at Queen's University of Belfast.
Sir Edward Frankland, was an English chemist. He was one of the originators of organometallic chemistry and introduced the concept of combining power or valence. An expert in water quality and analysis, he was a member of the second royal commission on the pollution of rivers, and studied London's water quality for decades. He also studied luminous flames and the effects of atmospheric pressure on dense ignited gas, and was one of the discoverers of helium.
Liquid air is air that has been cooled to very low temperatures, so that it has condensed into a pale blue mobile liquid. It is stored in specialized containers, such as vacuum flasks, to insulate it from room temperature. Liquid air can absorb heat rapidly and revert to its gaseous state. It is often used for condensing other substances into liquid and/or solidifying them, and as an industrial source of nitrogen, oxygen, argon, and other inert gases through a process called air separation.
A cryostat is a device used to maintain low cryogenic temperatures of samples or devices mounted within the cryostat. Low temperatures may be maintained within a cryostat by using various refrigeration methods, most commonly using cryogenic fluid bath such as liquid helium. Hence it is usually assembled into a vessel, similar in construction to a vacuum flask or Dewar. Cryostats have numerous applications within science, engineering, and medicine.
Morris William Travers, FRS was an English chemist who worked with Sir William Ramsay in the discovery of xenon, neon and krypton. His work on several of the rare gases earned him the name Rare Gas Travers in scientific circles. He was the founding director of the Indian Institute of Science, prior to which he served as a professor of Chemistry at the University College, Bristol, predecessor institution of the University of Bristol, on the recommendations of Sir William Ramsay, former principal of the University College.
Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The liquefaction of gases is a complicated process that uses various compressions and expansions to achieve high pressures and very low temperatures, using, for example, turboexpanders.
Industrial gases are the gaseous materials that are manufactured for use in industry. The principal gases provided are nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene, although many other gases and mixtures are also available in gas cylinders. The industry producing these gases is also known as industrial gas, which is seen as also encompassing the supply of equipment and technology to produce and use the gases. Their production is a part of the wider chemical Industry.
This is a timeline of the history of hydrogen technology.
A refrigerated transport Dewar is a refrigerated transport vessel with an insulated Dewar flask (vacuum) design to carry cryogenic liquid. To prevent pressure build-up they are equipped with safety relief valves and/or rupture discs. The liquid can be withdrawn as a gas by passing liquid through an internal vaporizer or as a liquid under its own vapour pressure.
An air separation plant separates atmospheric air into its primary components, typically nitrogen and oxygen, and sometimes also argon and other rare inert gases.
A cryogenic storage dewar is a specialised type of vacuum flask used for storing cryogens, whose boiling points are much lower than room temperature. It is named after inventor James Dewar, who developed it for his own work. They are commonly used in low-temperature physics and chemistry.