William Crookes
Encyclopedia
Sir William Crookes, OM, FRS (17 June 1832 – 4 April 1919) was a British chemist and physicist who attended the Royal College of Chemistry
, London, and worked on spectroscopy
. He was a pioneer of vacuum tube
s, inventing the Crookes tube
.
, might have been expected to lead him, but on new compounds of selenium
. These formed the subject of his first published papers in 1851.
Leaving the Royal College, he became superintendent of the meteorological department at the Radcliffe Observatory
in Oxford
in 1854, and in 1855 was appointed lecturer in chemistry at the Chester Diocesan Training College
.
Married now and living in London, he was devoted mainly to independent work. After 1880, he lived at 7 Kensington Park Gardens, where all his later work was carried out in his private laboratory. Crookes's life was one of unbroken scientific activity. The breadth of his interests, ranging over pure and applied science, economic and practical problems, and psychical research, made him a well-known personality, and he received many public and academic honours. In 1859, he founded the Chemical News, a science magazine which he edited for many years and conducted on much less formal lines than is usual with journals of scientific societies.
Crookes was knighted in 1897, and in 1910 received the Order of Merit
.
, from the Greek thallos, a green shoot. Crookes also identified the first known sample of helium
, in 1895. He was the inventor of the Crookes radiometer
, which today is made and sold as a novelty item. He also developed the Crookes tube
s, investigating cathode ray
s.
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 ray
s, 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 tube
s for the study of physical phenomena. He was, as a consequence, one of the first scientists to investigate what are now called plasmas
and identified it as the fourth state of matter in 1879. He also devised one of the first instruments for the study of nuclear radioactivity, the spinthariscope
.
, 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, announced in 1861, and made with the help of spectroscopy. By this work his reputation became firmly established, and he was elected a fellow of the Royal Society in 1863.
Crookes' attention had been attracted to the vacuum balance in the course of thallium research. He soon discovered the phenomenon upon which depends the action of the Crookes radiometer
, in which a system of vanes, each blackened on one side and polished on the other, is set in rotation when exposed to radiant energy. Crookes did not, however, provide the true explanation of this apparent "attraction and repulsion resulting from radiation
".
He published numerous papers on spectroscopy
and conducted research on a variety of minor subjects. In addition to various technical books, he wrote a standard treatise on Select Methods in Chemical Analysis in 1871, and a small book on diamonds in 1909.
s, showing that they travel in straight lines, cause fluorescence
in objects upon which they impinge, and by their impact produce great heat. He believed that he had discovered a fourth state of matter, which he called "radiant matter", but his theoretical views on the nature of "radiant matter" proved to be mistaken. He believed the rays to consist of streams of particles of ordinary molecular magnitude. It remained for Sir J. J. Thomson
to discover their subatomic nature, and to prove that cathode rays consist of streams of negative electrons, that is, of negatively 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.
In 1903, Crookes turned his attention to the newly discovered phenomenon of radioactivity, achieving the separation from uranium
of its active transformation product, uranium-X (later established to be protactinium
). He observed the gradual decay
of the separated transformation product, and the simultaneous reproduction of a fresh supply in the original uranium. At about the same time as this important discovery, he observed that when "p-particles", ejected from radio-active substances, impinge upon zinc sulfide
, each impact is accompanied by a minute scintillation, an observation which forms the basis of one of the most useful methods in the technique of radioactivity.
(Crookes 1870). Judging from family letters, Crookes had already developed a favorable view of Spiritualism by 1869 (Doyle 1926: volume 1, 232 – 233). In this he was possibly influenced by the untimely death of his young brother Philip in 1867 at age 21 from yellow fever contracted while on an expedition to lay a telegraph cable from Cuba to Florida (Crookes 1868). Nevertheless, he was determined to conduct his inquiry impartially and described the conditions he imposed on mediums as follows: "It must be at my own house, and my own selection of friends and spectators, under my own conditions, and I may do whatever I like as regards apparatus" (Doyle 1926: volume 1, 177). Among the mediums he studied were Kate Fox
, Florence Cook, and Daniel Dunglas Home
(Doyle 1926: volume 1, 230-251). Among the phenomena he witnessed were movement of bodies at a distance, rappings, changes in the weights of bodies, levitation, appearance of luminous objects, appearance of phantom figures, appearance of writing without human agency, and circumstances which "point to the agency of an outside intelligence".
To find support and assistance for his research, he joined the Society for Psychical Research
.
His report on this research in 1874, concluded that these phenomena could not be explained as conjuring, and that further research would be useful. Crookes was not alone in his views. Fellow scientists who came to believe in Spiritualism included Alfred Russel Wallace
, Oliver Lodge, Lord Rayleigh, and William James
(Doyle 1926: volume 1, 62). Nevertheless, most scientists were convinced that Spiritualism was fraudulent, and Crookes' final report so outraged the scientific establishment "that there was talk of depriving him of his Fellowship of the Royal Society." Crookes then became much more cautious and didn't discuss his views publicly until 1898, when he felt his position was secure. From that time until his death in 1919, letters and interviews show that Crookes was a believer in Spiritualism (Doyle 1926: volume 1, 169 – 170, 249 – 251).
He died in London on 4 April 1919, two years after his wife. He is buried in London's Brompton Cemetery
.
Royal College of Chemistry
The Royal College of Chemistry was a college originally based on Oxford Street in central London, England. It operated between 1845 and 1872....
, London, and worked on spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
. He was a pioneer of vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s, inventing the Crookes tube
Crookes tube
A Crookes tube is an early experimental electrical discharge tube, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, that is electrons, were discovered....
.
Early years
William Crookes was born in London, the eldest son of Joseph Crookes, a tailor of north-country origin, and his second wife, Mary Scott.Rise as prominent chemist
From 1850 to 1854 he filled the position of assistant in the college, and soon embarked upon original work, not in organic chemistry where the inspiration of his teacher, August Wilhelm von HofmannAugust Wilhelm von Hofmann
August Wilhelm von Hofmann was a German chemist.-Biography:Hofmann was born at Gießen, Grand Duchy of Hesse. Not intending originally to devote himself to physical science, he first took up the study of law and philology at Göttingen. But he then turned to chemistry, and studied under Justus von...
, might have been expected to lead him, but on new compounds of selenium
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
. These formed the subject of his first published papers in 1851.
Leaving the Royal College, he became superintendent of the meteorological department at the Radcliffe Observatory
Radcliffe Observatory
Radcliffe Observatory was the astronomical observatory of Oxford University from 1773 until 1934, when the Radcliffe Trustees sold it and erected a new observatory in Pretoria, South Africa. It is a grade I listed building.- History :...
in Oxford
Oxford
The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...
in 1854, and in 1855 was appointed lecturer in chemistry at the Chester Diocesan Training College
University of Chester
The University of Chester is a public research university located in Chester, United Kingdom. The University, based on a main campus in Chester and a smaller campus in Warrington, offers a range of foundation, undergraduate and postgraduate courses, as well as undertaking academic research.Chester...
.
Married now and living in London, he was devoted mainly to independent work. After 1880, he lived at 7 Kensington Park Gardens, where all his later work was carried out in his private laboratory. Crookes's life was one of unbroken scientific activity. The breadth of his interests, ranging over pure and applied science, economic and practical problems, and psychical research, made him a well-known personality, and he received many public and academic honours. In 1859, he founded the Chemical News, a science magazine which he edited for many years and conducted on much less formal lines than is usual with journals of scientific societies.
Crookes was knighted in 1897, and in 1910 received the Order of Merit
Order of Merit
The Order of Merit is a British dynastic order recognising distinguished service in the armed forces, science, art, literature, or for the promotion of culture...
.
Discoveries
In 1861, Crookes discovered a previously unknown element with a bright green emission line in its spectrum and named the element thalliumThallium
Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray poor metal resembles tin but discolors when exposed to air. The two chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861 by the newly developed method of flame spectroscopy...
, from the Greek thallos, a green shoot. Crookes also identified the first known sample of helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
, in 1895. He was the inventor of the Crookes radiometer
Crookes radiometer
The Crookes radiometer, also known as the light mill, consists of an airtight glass bulb, containing a partial vacuum. Inside are a set of vanes which are mounted on a spindle. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement...
, which today is made and sold as a novelty item. He also developed the Crookes tube
Crookes tube
A Crookes tube is an early experimental electrical discharge tube, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, that is electrons, were discovered....
s, investigating cathode ray
Cathode ray
Cathode rays are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite of the negative electrode is observed to glow, due to electrons emitted from and travelling perpendicular to the cathode Cathode...
s.
In his investigations of the conduction of electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
in low pressure gases, he discovered that as the pressure was lowered, the negative electrode (cathode) appeared to emit rays (the so-called cathode ray
Cathode ray
Cathode rays are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite of the negative electrode is observed to glow, due to electrons emitted from and travelling perpendicular to the cathode Cathode...
s, now known to be a stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...
of free electrons, and used in cathode ray display devices
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
). As these examples indicate, he was a pioneer in the construction and use of vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s for the study of physical phenomena. He was, as a consequence, one of the first scientists to investigate what are now called plasmas
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
and identified it as the fourth state of matter in 1879. He also devised one of the first instruments for the study of nuclear radioactivity, the spinthariscope
Spinthariscope
A Spinthariscope is a device for observing individual nuclear disintegrations caused by the interaction of ionizing radiation with a phosphor or scintillator.The spinthariscope was invented by William Crookes in 1903...
.
Legacy
Crookes worked over both fields of chemistry and physics. Its salient characteristic was the originality of conception of his experiments, and the skill of their execution.Chemistry
Crookes was always more effective in experiment than in interpretation. The method of spectral analysisSpectrum analysis
Spectrum, also known as emission spectrochemical analysis, is the original scientific method of charting and analyzing the chemical properties of matter and gases by looking at the bands in their optical spectrum...
, introduced by Bunsen
Robert Bunsen
Robert Wilhelm Eberhard Bunsen was a German chemist. He investigated emission spectra of heated elements, and discovered caesium and rubidium with Gustav Kirchhoff. Bunsen developed several gas-analytical methods, was a pioneer in photochemistry, and did early work in the field of organoarsenic...
and Kirchhoff
Gustav Kirchhoff
Gustav Robert Kirchhoff was a German physicist who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects...
, was received by Crookes with great enthusiasm and to great effect. His first important discovery was that of the element thallium, announced in 1861, and made with the help of spectroscopy. By this work his reputation became firmly established, and he was elected a fellow of the Royal Society in 1863.
Crookes' attention had been attracted to the vacuum balance in the course of thallium research. He soon discovered the phenomenon upon which depends the action of the Crookes radiometer
Crookes radiometer
The Crookes radiometer, also known as the light mill, consists of an airtight glass bulb, containing a partial vacuum. Inside are a set of vanes which are mounted on a spindle. The vanes rotate when exposed to light, with faster rotation for more intense light, providing a quantitative measurement...
, in which a system of vanes, each blackened on one side and polished on the other, is set in rotation when exposed to radiant energy. Crookes did not, however, provide the true explanation of this apparent "attraction and repulsion resulting from radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
".
He published numerous papers on spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
and conducted research on a variety of minor subjects. In addition to various technical books, he wrote a standard treatise on Select Methods in Chemical Analysis in 1871, and a small book on diamonds in 1909.
Physics
Crookes investigated the properties of cathode rayCathode ray
Cathode rays are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite of the negative electrode is observed to glow, due to electrons emitted from and travelling perpendicular to the cathode Cathode...
s, showing that they travel in straight lines, cause fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
in objects upon which they impinge, and by their impact produce great heat. He believed that he had discovered a fourth state of matter, which he called "radiant matter", but his theoretical views on the nature of "radiant matter" proved to be mistaken. He believed the rays to consist of streams of particles of ordinary molecular magnitude. It remained for Sir J. J. Thomson
J. J. Thomson
Sir Joseph John "J. J." Thomson, OM, FRS was a British physicist and Nobel laureate. He is credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer...
to discover their subatomic nature, and to prove that cathode rays consist of streams of negative electrons, that is, of negatively electrified particles whose mass is only 1/1840 that of a hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
atom. Nevertheless, Crookes's experimental work in this field was the foundation of discoveries which eventually changed the whole of chemistry and physics.
In 1903, Crookes turned his attention to the newly discovered phenomenon of radioactivity, achieving the separation from uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
of its active transformation product, uranium-X (later established to be protactinium
Protactinium
Protactinium is a chemical element with the symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. It forms various chemical compounds where protactinium is usually present in the oxidation state +5, but can also assume...
). He observed the gradual decay
Radioactive decay
Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...
of the separated transformation product, and the simultaneous reproduction of a fresh supply in the original uranium. At about the same time as this important discovery, he observed that when "p-particles", ejected from radio-active substances, impinge upon zinc sulfide
Zinc sulfide
Zinc sulfide is a inorganic compound with the formula ZnS. ZnS is the main form of zinc in nature, where it mainly occurs as the mineral sphalerite...
, each impact is accompanied by a minute scintillation, an observation which forms the basis of one of the most useful methods in the technique of radioactivity.
Spiritualism
In 1870 Crookes decided that science had a duty to study preternatural phenomena associated with SpiritualismSpiritualism
Spiritualism is a belief system or religion, postulating the belief that spirits of the dead residing in the spirit world have both the ability and the inclination to communicate with the living...
(Crookes 1870). Judging from family letters, Crookes had already developed a favorable view of Spiritualism by 1869 (Doyle 1926: volume 1, 232 – 233). In this he was possibly influenced by the untimely death of his young brother Philip in 1867 at age 21 from yellow fever contracted while on an expedition to lay a telegraph cable from Cuba to Florida (Crookes 1868). Nevertheless, he was determined to conduct his inquiry impartially and described the conditions he imposed on mediums as follows: "It must be at my own house, and my own selection of friends and spectators, under my own conditions, and I may do whatever I like as regards apparatus" (Doyle 1926: volume 1, 177). Among the mediums he studied were Kate Fox
Fox sisters
The Fox sisters were three sisters from New York who played an important role in the creation of Spiritualism. The three sisters were Leah Fox , Margaret Fox and Kate Fox . The two younger sisters used "rappings" to convince their much older sister and others that they were communicating with...
, Florence Cook, and Daniel Dunglas Home
Daniel Dunglas Home
Daniel Dunglas Home was a Scottish physical medium with the reported ability to levitate to a variety of heights, speak with the dead, and to produce rapping and knocks in houses at will. His biographer Peter Lamont opines that he was one of the most famous men of his era...
(Doyle 1926: volume 1, 230-251). Among the phenomena he witnessed were movement of bodies at a distance, rappings, changes in the weights of bodies, levitation, appearance of luminous objects, appearance of phantom figures, appearance of writing without human agency, and circumstances which "point to the agency of an outside intelligence".
To find support and assistance for his research, he joined the Society for Psychical Research
Society for Psychical Research
The Society for Psychical Research is a non-profit organisation in the United Kingdom. Its stated purpose is to understand "events and abilities commonly described as psychic or paranormal by promoting and supporting important research in this area" and to "examine allegedly paranormal phenomena...
.
His report on this research in 1874, concluded that these phenomena could not be explained as conjuring, and that further research would be useful. Crookes was not alone in his views. Fellow scientists who came to believe in Spiritualism included Alfred Russel Wallace
Alfred Russel Wallace
Alfred Russel Wallace, OM, FRS was a British naturalist, explorer, geographer, anthropologist and biologist...
, Oliver Lodge, Lord Rayleigh, and William James
William James
William James was a pioneering American psychologist and philosopher who was trained as a physician. He wrote influential books on the young science of psychology, educational psychology, psychology of religious experience and mysticism, and on the philosophy of pragmatism...
(Doyle 1926: volume 1, 62). Nevertheless, most scientists were convinced that Spiritualism was fraudulent, and Crookes' final report so outraged the scientific establishment "that there was talk of depriving him of his Fellowship of the Royal Society." Crookes then became much more cautious and didn't discuss his views publicly until 1898, when he felt his position was secure. From that time until his death in 1919, letters and interviews show that Crookes was a believer in Spiritualism (Doyle 1926: volume 1, 169 – 170, 249 – 251).
Personal life
In 1856 he married Ellen, daughter of William Humphrey, of Darlington, by whom he fathered three sons and a daughter.He died in London on 4 April 1919, two years after his wife. He is buried in London's Brompton Cemetery
Brompton Cemetery
Brompton Cemetery is located near Earl's Court in South West London, England . It is managed by The Royal Parks and is one of the Magnificent Seven...
.
External links
- Crookes, William. 1868. "In Memoriam. The Last Letters of John Philip Edwin Crookes."
- Crookes, William. 1870. "Spiritualism Viewed by the Light of Modern Science." Quarterly Journal of Science. July 1870.
- Crookes, William. 1874. "Notes of an Enquiry into the Phenomena called Spiritual during the Years 1870-1873." Quarterly Journal of Science. January 1874.
- Doyle, Arthur Conan. The History of Spiritualism. New York: G.H. Doran, Co. Volume 1: 1926 Volume 2: 1926
- Crookes, William. 1909. Diamonds: on treatments, physical and chemical properties of loose diamonds
- Hinshelwood, Cyril Norman, "William Crookes, A Victorian man of science". 1927. (Much material on this page was taken from Hinshlewood's article)
- The Cathode Ray Tube site
- Photo of gravesite