Sir William Crookes (; 17 June 1832 – 4 April 1919) was an English chemist and physicist who attended the Royal College of Chemistry, now part of Imperial College London, and worked on spectroscopy. He was a pioneer of vacuum tubes, inventing the Crookes tube, which was made in 1875. Observing cathode rays generated in these tubes, Crookes posited that "radiant matter" was a unique fourth state of matter, a foundational contribution to plasma physics.
He is credited with discovering the element thallium, announced in 1861, with the help of spectroscopy. He was also the first to describe the spectrum of terrestrial helium, in 1865. Crookes was the inventor of the Crookes radiometer, but did not discern the true explanation of the phenomenon he detected.
According to historian William H. Brock, Crookes's later work on ultraviolet eye protection arose from 1907 Royal Society investigations into cataracts among furnace and glass workers. Developed in partnership with Wigmore Street opticians Sir William Wingate and Frank Melson Wingate, by 1918 the resulting 'Crookes Lenses' under Melson Wingate Ltd combined scientific research with practical industrial safety as a manufactured product. Brock argues that this work laid the foundation for the modern sunglasses industry, while the lenses themselves were applied to industrial, military and aviation applications for much of the twentieth century, until modern sunglass branding gradually superseded them.
Biography Early years William Crookes was born in London in 1832, the eldest of eight surviving children (eight others died young) of Joseph Crookes (1792–1889), a wealthy tailor and real estate investor of north-country origin, and his second wife, Mary (née Scott; 1806–1884). Joseph Crookes's father, William (1734–1814), was also a tailor, whose grandfather, John Crookes (b. 1660), had been Mayor of Hartlepool, County Durham on three occasions.William Crookes (1832–1919) and the Commercialization of Science, William H. Brock, Routledge, 2008; Routledge, pp. 3–4
Joseph Crookes had had five children with his first wife; two sons from that marriage, Joseph and Alfred, took over the tailoring business, leaving William free to choose his own path. In 1848, at age 16, Crookes entered the Royal College of Chemistry (now the Imperial College chemistry department) to study organic chemistry. Crookes lived with his parents about three miles from the College in Oxford Street. His father's shop was about half a mile away. Crookes paid £25 for his first year's tuition and had to provide his own apparatus and some of the more expensive chemicals. At the end of his first year, Crookes won the Ashburton scholarship which covered his second year's tuition. At the end of his second year, Crookes became a junior assistant to August Wilhelm von Hofmann, doing laboratory demonstrations and helping with research and commercial analysis. In October 1851, Crookes was promoted to senior assistant, a position he held until 1854.
Although Crookes revered Hofmann, he did not share his primary interest in organic chemistry. One of Crookes's students was the Reverend John Barlow, Secretary of the Royal Institution, who chose to take a course in analytical chemistry. Through Barlow, Crookes met scientists such as George Gabriel Stokes and Michael Faraday. Such friends reinforced Crookes's interest in optical physics which was respected by Hofmann. By 1851, Crookes's interest in photography and optics caused his father to build him a laboratory in the garden at home for his research.
When Crookes embarked upon original work, it wasn't in organic chemistry, but rather into new compounds of selenium. These were the subject of his first published papers, in 1851. He worked with Manuel Johnson at the Radcliffe Observatory in Oxford in 1854, where he adapted the recent innovation of wax paper photography to machines built by Francis Ronalds to continuously record meteorological parameters. In 1855 he was appointed lecturer in chemistry at the Chester Diocesan Training College.
In April 1856 Crookes married Ellen, daughter of William Humphrey of Darlington. Since staff at Chester were required to be bachelors, he had to resign his position. William's father, Joseph Crookes, gave the couple a house at 15 Stanley Street, Brompton. Ellen's mother, Mrs. Humphrey, lived with them for the rest of her life, nearly forty years. A devoted couple, William and Ellen Crookes had six sons and three daughters. Their first child, Alice Mary (born 1857, later Mrs. Cowland) remained unmarried for forty years, living with her parents and working as an assistant to her father. Two of Crookes's sons became engineers, and two lawyers.
Married and living in London, Crookes sought to support his new family through independent work as a photographic chemist. In 1859, he founded the Chemical News, a science magazine which he edited for many years and conducted on much less formal lines than was usual for the journals of scientific societies. In his Chemical News Crookes published Faraday's A Course of Six Lectures on the Various Forces of Nature and in 1860 he edited the lectures and published it as a book (he also wrote the Preface). Between 1864 and 1869, he was also involved with the Quarterly Journal of Science. At various times he edited the Journal of the Photographic Society and the Photographic News.
Middle years
Crookes was effective in experimentation. The method of spectral analysis, introduced by Bunsen and Kirchhoff, was received by Crookes with great enthusiasm and to great effect.
His first important discovery was that of the element thallium, made with the help of flame spectroscopy. Crookes discovered a previously unknown element with a bright green emission line in its spectrum. He named the element thallium, from Greek , , meaning "a green shoot or twig". Crookes's findings were published on 30 March 1861.Crookes, William (30 March 1861) "On the existence of a new element, probably of the sulphur group," Chemical News, vol. 3, pp. 193–194; reprinted in: Crookes, William (18 May 1861) "Further remarks on the supposed new metalloid," Chemical News, vol. 3, p. 303.Crookes, William (19 June 1862) "Preliminary researches on thallium," Proceedings of the Royal Society of London, vol. 12, pages 150–159.
Thallium was also independently discovered by Frenchman Claude Auguste Lamy, who had the advantage of access to large amounts of materials via his brother-in-law, Charles Frédéric Kuhlmann. Both Crookes and Lamy isolated the element in 1862.Lamy, A. (16 May 1862) "De l'existencè d'un nouveau métal, le thallium," Comptes Rendus, vol. 54, pages 1255–1262.
Crookes was elected a fellow of the Royal Society in 1863. Crookes wrote a standard treatise on Select Methods in Chemical Analysis in 1871.
In 1866, Adolf Erik Nordenskiöld identified a rare mineral from Skrikerum as a selenide of copper, thallium, and silver (), and named the mineral crookesite in honor of Sir William Crookes.
Crookes developed the Crookes tube,The difference between "Crookes tubes" and "Geissler tubes" is this: In a Geissler tube the exhaustion is very much less than in a Crookes tube, the light which we see in the Geissler tube being due to the luminescence of the residual gas. (Transactions, Volume 9. Hertfordshire Natural History Society and Field Club. The Club, 1898. Page 136.) investigating cathode rays. He published numerous papers on spectroscopy and conducted research on a variety of minor subjects. In his investigations of the conduction of electricity in low pressure gases, he discovered that as the pressure was lowered, the negative electrode (cathode) appeared to emit rays (the so-called "cathode rays", now known to be a stream of free electrons, and used in cathode-ray display devices). As these examples indicate, he was a pioneer in the construction and use of vacuum tubes for the study of physical phenomena.Alexander E. Outerbridge, Jr., A Fourth State of Matter. Lecture delivered before the Franklin Institute, 17 February 1881. Journal of the Franklin Institute of the State of Pennsylvania, Volume 81. By Franklin Institute (Philadelphia, Pa.). Page 287+. He was, as a consequence, one of the first scientists to investigate what is now called a plasma and identified it as the fourth state of matter in 1879.William Crookes, On Radiant Matter. Lecture delivered before the British Association for the Advancement of Science, at Sheffield, Friday, 22 August 1879. The Popular Science Monthly, Volume 16. D. Appleton, 1880. Pg157+ He also devised one of the first instruments for studying nuclear radioactivity, the spinthariscope.Crookes, W. Certain Properties of the Emanations of Radium. Chemical News; Vol. 87:241; 1903.
Crookes investigated the properties of cathode rays, showing that they travel in straight lines, cause fluorescence when they fall on some substances, and that their impact can produce great heat. He believed that he had discovered a fourth state of matter, which he called "radiant matter",Radio-activity induced by the oscillatory discharge, or, The subsequent radio-active emanation from substances exposed to the Tesla oscillatory discharge. Harry Marshall Diemer, Ralph Stuart Cooper. Cornell University, 1903. Page 43+. but his theoretical views on the nature of "radiant matter" were to be superseded.Chemist & Druggist, Volume 60. Benn Brothers., 1902. Pg 268. He believed the rays to consist of streams of particles of ordinary molecular magnitude. It remained for Sir J. J. Thomson to expound on the subatomic nature of cathode rays (consisting of streams of negative electronsNegatively electrified particles whose mass is only 1/1840 that of a hydrogen atom). Nevertheless, Crookes's experimental work in this field was the foundation of discoveries which eventually changed the whole of chemistry and physics.
Crookes's attention had been attracted to the vacuum balance in the course of his research into thallium. He soon discovered the phenomenon which drives the movement in a Crookes radiometer, in which a set of vanes, each blackened on one side and polished on the other, rotate when exposed to radiant energy. Crookes did not, however, provide the true explanation of this apparent "attraction and repulsion resulting from radiation".., Improvement in Apparatus For Indicating The Intensity of Radiation
After 1880, Crookes lived at 7 Kensington Park Gardens in the fashionable area of Notting Hill. His household included a large multigenerational family and a number of servants. There all his later work was done, in what was then "the finest private laboratory in Britain". It comprised an entire floor of the house and included three interconnected laboratory rooms, for chemistry, physics, and mechanical construction, and a library. Crookes was able to purchase the house and build the laboratory because of his income from the National Guano Company and from various patents.
By 1880 Crookes employed a paid full-time scientific assistant (first Charles Gimingham and after 1883 James Gardiner). He was also helped by his daughter Alice, who was "adept at fractionating rare earth elements" and "no mean interpreter of spectra".
His daily routine was to manage his commercial affairs in the morning, do further business or go to scientific meetings in the afternoon, eat dinner at 7, work in his library from 8 to 9, and then in the laboratory until after midnight. From his home, Crookes could easily reach the Chemical News offices, the Royal Society, the Chemica Society, and the Athenaeum Club.
On 16 January 1884, Crookes's father died. Crookes's daughter Florence died of scarlet fever in the same week. Joseph Crookes's estate was left in trust, divided between his three surviving sons, Alfred, William and Frank. Combined with his previous income, this ensured that Crookes was very well off.
In 1886, Crookes was elected as a member to the American Philosophical Society.