Greetings from iainthepict. This blog of mine is meant to be like a 'Book of Days' or a kind of 'Scottish Year Book' if you will. The idea was to present an event for each day of the year. Somewhere in here, you can find out what happened, affecting Scotland and the Scots, on any given day of the year. Your comments and observations are very welcome.
The photograph is by Sam Perkins (check him out on Facebook at Sam Perkins Photography) and was taken near Oban.

Sunday, 19 December 2010

Thomas Graham

Thomas Graham, chemist and physicist, was born on the 20th of December, 1805.

Thomas Graham was an inquisitive kind of a guy before he became an eminent chemist. He wanted to know things and from an early age was always asking “Why?” The difference between him and most kids was that he never stopped asking. He quickly progressed from the annoyingly stereotypical and learned to pose questions like, “Don’t you think, Doctor..?” Another difference in Graham’s case was the remarkable zeal with which he pursued his research. Unlike other chemists and a lot of scientists who engaged in arguments based on opinion, Graham quietly got on with his research, carefully and conscientiously, and then, and only then, published his results and conclusions. By the mid-1840s, Graham was acknowledged as the leading chemist of his day. He is often referred to as ‘the father of colloid chemistry’ and is remembered for ‘Graham’s Law’, which makes him the ‘father of physical chemistry’.

Graham made three major contributions to the science of chemistry, one of them being his eponymous ‘Law’, which resulted from his studies during the 1820s on the diffusion of gases, and the other two being in the areas of the aforementioned colloid chemistry and the determination of the formulas of PxOy polyatomic ions. In addition, it seems Graham’s work on the absorption of hydrogen gas by palladium metal has taken on more significance in light of the ‘cold fusion controversy’. If you are unsure of colloid chemistry, you’re probably aware of dialysis, which was the result of Graham’s work on colloids and critically, the direct ancestor of today’s indispensible ‘artificial kidney’ or dialysis machines.

Graham established the law that bears his name in 1831, after becoming intrigued by the observations of Johann Wolfgang Döbereiner. The German was confused about the behaviour of a cracked bottle of hydrogen partially submerged in a tank of water. In fact, it was losing hydrogen more quickly than it was gaining air and Graham’s research led him to conclusively prove that  the rate of diffusion (or effusion) of a gas at constant pressure and temperature is inversely proportional to the square root of its density or molar mass. His law has since found use in many different areas of science. It provides a basis for separating isotopes by diffusion, a method that played a crucial role in the development of the atomic bomb.

Graham also studied diffusion, a term he coined, in liquids and that led to his classification of two types of substance; colloids (from Greek ‘kolla’; glue), which diffuse slowly, and crystalloids, which diffuse quickly. He then found that substances of the two types differed markedly in their ability to pass through a membrane – the process of osmosis – and as a result, he developed a method to separate them. He called the process dialysis and his machine a ‘dialyzer’. Apart from diffusion, most of the nomenclature in the field, such as sol, gel, peptization, and syneresis, comes from Graham’s work. Graham’s interests were broad and interestingly, he is known as the first to have advocated the use of denatured alcohol, suggesting that ethanol intended for purposes other than drinking be poisoned to prevent its consumption.

Thomas Graham was born in Glasgow on the 20th of December, 1805. In 1811, Thomas went to a preparatory school in Glasgow and in 1814 he advanced to the High School, where he spent four years studying, amongst other subjects, Latin and Greek. He went to Glasgow University at the age of fourteen in 1819 and there, he attended the classes of Thomas Thomson, the Professor of Chemistry. Graham’s father wanted him to become a Church of Scotland Minister, but intrigued by chemistry, Graham determined to persist with science. Thomson’s influence was one thing, but early on, Graham had impressed his usually irascible Professor by having asked, “Don’t you think, Doctor, that when liquids absorb gases the gases themselves become liquids?” Graham gained his M.A. in 1826 and for two years, worked for Thomas Charles Hope at the University of Edinburgh. He then returned to Glasgow, where he privately taught mathematics and chemistry, at a laboratory in Portland Street, for a year, and in 1829, he became an assistant at a mechanics institute.

The decisive step in Graham’s life came in 1830, when he was appointed Professor of Chemistry at Anderson’s ‘University’ (later the Royal College of Science and Technology and later still, the University of Strathclyde) in Glasgow, where he spent the next seven years. He was elected Fellow of the Royal Society in 1834 and in 1837, the same year he received the first of three Medals (two ‘Royals’ and a ‘Copley’) from the Royal Society, he moved to London to become Professor of Chemistry at the recently founded University College. It was whilst there that he began publishing his ‘Elements of Chemistry’ texts, which became the standard textbook in Britain and throughout Europe. He helped found the Cavendish Society and, in 1841, the Chemical Society of London whose first President he became.

His last post was Master of the Mint, a position once occupied by Isaac Newton and one that ceased to exist after Graham’s death. When he took up the job at the Mint, it was generally expected that he would treat it as a sinecure, but Graham took it so seriously that he stopped all his research for several years while he reorganised its operation. Thomas Graham died in London on the 16th of September, 1869. In an 1869 obituary in ‘Nature’ by A. W. Williamson, it was stated that Graham’s scientific influence extended beyond his researches and that “his greatness is to be measured not merely by the amount and importance of the knowledge which he thus gave, but even more by [his] singleness and strength of purpose”. Williamson goes on to say that “In many of his ideas, Graham was in advance of his contemporaries, and it might be difficult to find a chemist …whose results, in each direction in which he has worked, may more safely be expected to stand the test of future investigations”.

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