Thomas Graham (chemist)
Thomas Graham (born December 21, 1805 in Glasgow , † September 11, 1869 in London ) was a British chemist and physical chemist . Graham studied the flow rates of gases through a very thin hole in a vacuum. The flow velocity was inversely proportional to the square root of the molecular mass of the gas. He also determined the diffusion of salts in liquids. Graham also researched the basis for the diffusion of substances through a membrane (dialysis), colloids (macromolecular substances) could not penetrate the membrane.
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Thomas Graham was the son of a successful factory owner in Glasgow. His father wanted him to be a pastor. However, Thomas had no inclination to do so, he wanted to study natural sciences - later this broke the relationship between father and son. From 1819 he occupied himself with studies of mathematics, physics and chemistry in the University of Glasgow. Graham completed his science studies with a Master of Arts, but received no more financial contributions from the wealthy father.
After several poor years as an assistant, he became professor of chemistry at Anderson's College in Glasgow in 1830 and went to university college in London as professor of chemistry in 1837. His lectures were very popular among the students, so that he had high college income. In 1841, Graham wrote a textbook on chemistry that remained the best chemistry textbook ( Elements of Chemistry ) in English for many decades . The German translation by Friedrich Julius Otto also became a standard textbook for chemistry in Germany. Graham was a member of the Royal Society as early as 1836, from 1838 to 1841 he worked in Germany for Liebig's Annalen der Chemie und Pharmacie , in 1841 he founded the Chemical Society of London with other chemists and became its first President. In 1828 he was elected a Fellow of the Royal Society of Edinburgh (RSE); since 1845 he was an Honorary Fellow of the RSE. In 1840 he was elected a corresponding member and in 1853 an external member of the Bavarian Academy of Sciences . August Wilhelm von Hofmann , who knew Graham well from his student days at Liebig, emigrated to England in 1845. There he also became a member of this British Society in 1845 and even its board of directors from 1861 to 1863. After his return to Germany in 1865, Hofmann founded the German Chemical Society in Berlin in 1867, based on the British model .
In 1854 he also took over the management of the Royal Mint (which Isaac Newton and John Herschel had also directed before him ), d. H. he was given responsibility for making money. Graham's father slowly reconciled with Thomas after his scientific and professional successes. From 1854 to 1860, Graham no longer worked in scientific research. In 1847 Graham was elected to the Académie des Sciences , 1864 to the American Academy of Arts and Sciences and 1866 to the Russian Academy of Sciences in St. Petersburg .
Scientific achievements
In 1831 Graham published a work on salt-like compounds from alcohol and salt ( alcoholates ) and their water of crystallization.
In 1833, Graham explained the diversity of phosphoric acid and its various types of salt formation with different levels of hydrogen. Some phosphoric acid salts gave an acidic reaction even in water. The water acts as a base that absorbs hydrogen from the certain phosphoric acid salts. Stronger bases took up even more hydrogen. Consequently, there had to be a different number of hydrogen atoms on the phosphoric acid.
Diffusion of gases
In 1832 he published Graham's law , named after him , which deals with the interaction during the diffusion of gases. Döbereiner had put a slightly opened measuring cylinder with hydrogen gas upside down in a water basin. The liquid column rose in the measuring cylinder. The gas that exited through the fine crack at the same pressure had to be faster than the gas that flowed in ( outflow law ). Graham now investigated in a similar way various gases separated from one another by a very thin glass tube. He found that the root gas density (that is, the molecular mass of the gas particles) is inversely proportional to the speed of the gas. This law formed the basis for the later kinetic gas theory.
Diffusion of salts in liquids
Graham was now also interested in liquids and a possible transfer from a salty solution to a less salty one. Since he still had very little money to spend on complex experiments, he took a preparation glass and filled it to the brim with a concentrated saline solution. The preparation jar was now placed in a larger glass and then he carefully poured water into the larger glass up to just over the edge of the smaller preparation jar. Now he left the test arrangement and noted the time. Finally he distilled off the water in the outer glass and determined the mass. Salt had diffused from the saline solution into the water. Depending on the type of substances, he was also able to determine differences in the speed of migration, so that he could also separate salts from one another (e.g. chlorides from sulfates, carbonates, potassium salts from sodium salts).
Building on the diffusion experiments, Graham now investigated the migration of dissolved substances through a membrane . With this he developed chemical dialysis . He used leveled paper that was made into parchment paper by dipping it in sulfuric acid or zinc chloride. The parchment paper was placed on a bell-shaped glass vessel with a central glass tube (osmometer). Crystalline substances could diffuse through, other glue-like substances - the colloids - did not migrate through this membrane. He made this discovery in 1854, but did not have enough time to write it down until 1861.
From 1866 Graham investigated whether different gases could be separated by a membrane (rubber septum; metal foils). Graham discovered the connection between gaseous hydrogen and palladium and assumed that there must be a hydrogen-palladium bond.
Textbooks
Together with Friedrich Julius Otto he published a basic series of textbooks, the "Graham-Otto's detailed textbook on chemistry" in three volumes.
Honors
The Thomas Graham Prize of the Colloid Society was named after him.
literature
- Günther Bugge: The book of the great chemist , Verlag Chemie GmbH, Weinheim 1974, ISBN 3-527-25021-2 .
Fonts
- Thomas Graham's Textbook of Chemistry. Edited by Friedrich Julius Otto , 3 volumes, Vieweg, Braunschweig 1840–1843 (Volume 1: babel.hathitrust.org , Volume 2, 1st half: reader.digitale-sammlungen.de , Volume 2, 2nd half: reader.digitale -sammlungen.de ).
- Graham-Otto's extensive textbook on chemistry. 3 volumes in 5 sub-volumes, 3rd edition, Vieweg, from 1854 (edited by Hermann Kolbe , Johann Heinrich Buff , Friedrich Zamminer , Ernst von Meyer , Hermann Fehling , Hermann Kopp ), Volume 1: Physical Chemistry (1st Department: babel. hathitrust.org 1863), Volume 2: Inorganic Chemistry ( books.google.de 1863), Volume 3: Organic Chemistry ( books.google.de 1868).
Web links
- Article by / about Graham, Thomas in the Polytechnisches Journal
- The Late Professor Graham. ( Memento of November 28, 2016 in the Internet Archive ) Obituary by Alexander William Williamson , published in: Nature . Volume 1, No. 1, November 4, 1869.
swell
- ^ Fellows Directory. Biographical Index: Former RSE Fellows 1783–2002. (PDF) Royal Society of Edinburgh, accessed December 10, 2019 .
- ↑ Member entry by Prof. Dr. Thomas Graham (with picture) at the Bavarian Academy of Sciences , accessed on February 8, 2016.
- ↑ Th. Graham: About the movement of gases , Lieb. Ann. 76 , (1850), pp. 138-159
- ↑ Th. Graham: On the absorption and dialytic separation of gases by colloid septa. In: Philosophical Transactions of the Royal Society of London Vol. 156 (1866), pp. 399-439
- ^ Graham-Otto's textbook on chemistry
| personal data | |
|---|---|
| SURNAME | Graham, Thomas |
| BRIEF DESCRIPTION | British chemist |
| DATE OF BIRTH | December 21, 1805 |
| PLACE OF BIRTH | Glasgow |
| DATE OF DEATH | September 11, 1869 |
| Place of death | London |