Thomas Graham (20 December 1805 – 11 September 1869) was a Scottish

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

known for his pioneering work in dialysis and the

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

of gases. He is regarded as one of the founders of

colloid A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, while others exte ...

chemistry.

Life

Graham was born in

Glasgow Glasgow is the Cities of Scotland, most populous city in Scotland, located on the banks of the River Clyde in Strathclyde, west central Scotland. It is the List of cities in the United Kingdom, third-most-populous city in the United Kingdom ...

, Scotland and was educated at the High School of Glasgow. Graham's father was a successful textile manufacturer, and wanted his son to enter into the

Church of Scotland The Church of Scotland (CoS; ; ) is a Presbyterian denomination of Christianity that holds the status of the national church in Scotland. It is one of the country's largest, having 245,000 members in 2024 and 259,200 members in 2023. While mem ...

. Instead, defying his father's wishes, Graham became a student at the

University of Glasgow The University of Glasgow (abbreviated as ''Glas.'' in Post-nominal letters, post-nominals; ) is a Public university, public research university in Glasgow, Scotland. Founded by papal bull in , it is the List of oldest universities in continuous ...

in 1819. There he developed a strong interest in

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

, studying under Professor Thomas Thomson, who was impressed and influenced by the young man. He left the university after receiving his MA in 1824. He later studied medicine at the

University of Edinburgh The University of Edinburgh (, ; abbreviated as ''Edin.'' in Post-nominal letters, post-nominals) is a Public university, public research university based in Edinburgh, Scotland. Founded by the City of Edinburgh Council, town council under th ...

and then briefly taught chemistry at the Glasgow University Portland Street Medical School. In 1828 he was elected a Fellow of the

Royal Society of Edinburgh The Royal Society of Edinburgh (RSE) is Scotland's national academy of science and letters. It is a registered charity that operates on a wholly independent and non-partisan basis and provides public benefit throughout Scotland. It was establis ...

, his proposer was Edward Turner. He won the Society's Keith Medal for the period 1831–33. in 1830 he was appointed to be the first professor of chemistry at the Anderson's Medical School, a post later named the Freeland Chair of Chemistry. He also delivered lectures to the Glasgow Mechanics' Institution before moving to take up a professorship at the

University of London The University of London (UoL; abbreviated as Lond or more rarely Londin in Post-nominal letters, post-nominals) is a collegiate university, federal Public university, public research university located in London, England, United Kingdom. The ...

, where Graham founded the Chemical Society of London in 1841. In 1866, he was elected a foreign member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...

. His final position was the

Master of the Mint Master of the Mint is a title within the Royal Mint given to the most senior person responsible for its operation. It was an office in the governments of Scotland and England, and later Great Britain and then the United Kingdom, between the 16th ...

, where he stayed from 1855 until his death. He was the last person to hold that position: afterwards the post was amalgamated into the

Chancellor of the Exchequer The chancellor of the exchequer, often abbreviated to chancellor, is a senior minister of the Crown within the Government of the United Kingdom, and the head of HM Treasury, His Majesty's Treasury. As one of the four Great Offices of State, t ...

while all the actual responsibilities were transferred to the Deputy Master. He died in

Gordon Square Gordon Square is a public park square in Bloomsbury, London, England. It is part of the Bedford Estate and was designed as one of a pair with the nearby Tavistock Square. It is owned by the University of London. History and buildings The sq ...

in London but his body was returned to Glasgow for burial in the family plot at Glasgow Cathedral.

Publications

*''On the Law of Diffusion of Gases'' (1833)

Scientific works

Thomas Graham is known for his studies on the behavior of gases, which resulted in his formulation of two relationships, both since becoming known as "Graham's laws," the first regarding gas

, and the second regarding gas

effusion In physics and chemistry, effusion is the process in which a gas escapes from a container through a hole of diameter considerably smaller than the mean free path of the molecules. Such a hole is often described as a ''pinhole'' and the escape ...

. In the former case, Graham deduced that when measured repeatedly under the same conditions of pressure and temperature, the rate of diffusive mixing of a gas is inversely proportional to the square root of its density, and given the relationship between

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

and

molar mass In chemistry, the molar mass () (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical substance ( element or compound) is defined as the ratio between the mass () and the amount of substance ...

, also inversely proportional to the square root of its

. In the same way, in the latter case, regarding

of a gas through a pin hole in to a vacuum, Graham deduced that the rate of

of a gas is inversely proportional to the square root of its molar mass. These two are sometimes referred to as a combined law (describing both phenomena). In applied areas, Graham also made fundamental discoveries related to dialysis, a process used in research and industrial settings, as well as in modern health care. Graham's study of colloids resulted in his ability to separate colloids and crystalloids using a so-called "dialyzer", using technology that is a rudimentary forerunner of technology in modern

kidney dialysis Kidney dialysis is the process of removing excess water, solutes, and toxins from the blood in people whose kidneys can no longer perform these functions naturally. Along with kidney transplantation, it is a type of renal replacement therapy. ...

machines. These studies were foundational in the field known as

, and Graham is credited as one of its founders. He also proposed the association theory which claimed that the substances such as

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

that we now know are polymers are composed from smaller molecules hold together by unknown forces. It remained the most popular explanation until

Hermann Staudinger Hermann Staudinger (; 23 March 1881 – 8 September 1965) was a German organic chemist who demonstrated the existence of macromolecules, which he characterized as polymers. For this work he received the 1953 Nobel Prize in Chemistry. He is also ...

's macromolecular theory of 1920s.

Honours, activities, and recognition

* Elected an Honorary Fellow of the

(1828) receiving its Keith Medal for 1831–33 *

Fellow of the Royal Society Fellowship of the Royal Society (FRS, ForMemRS and HonFRS) is an award granted by the Fellows of the Royal Society of London to individuals who have made a "substantial contribution to the improvement of natural science, natural knowledge, incl ...

(1836) * First President of the Chemical Society of London (1841) *

Royal Medal The Royal Medal, also known as The Queen's Medal and The King's Medal (depending on the gender of the monarch at the time of the award), is a silver-gilt medal, of which three are awarded each year by the Royal Society. Two are given for "the mo ...

of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

(1837 and 1863) * Honorary doctorate (DCL) from the

University of Oxford The University of Oxford is a collegiate university, collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the List of oldest un ...

(1853) *

Copley Medal The Copley Medal is the most prestigious award of the Royal Society of the United Kingdom, conferred "for sustained, outstanding achievements in any field of science". The award alternates between the physical sciences or mathematics and the bio ...

of the Royal Society (1862) * Prix Jecker of the Paris Academy of Sciences (1862) * A statue of Graham, sculpted by William Brodie in

George Square George Square () is the principal Town square, civic square in the city of Glasgow, Scotland. It is one of six squares in the city centre, the others being Cathedral Square, Glasgow, Cathedral Square, St Andrew's Square, Glasgow, St Andrew's ...

in Glasgow was erected by the city in 1872George Square Thomas Graham Statue
Historic Environment Scotland * The Royal College of Science and Technology (the successor of Anderson's Institution, where Graham once worked, which ultimately became the University of Strathclyde), named its new Chemistry building the ''Thomas Graham Building'' in 1962. * The headquarters of the

Royal Society of Chemistry The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the ...

Cambridge Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north of London. As of the 2021 Unit ...

, England is named ''Thomas Graham House''

References

External links