Journal of the Society of Chemical

SUBJECT AREA: Chemical technology

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Born into a prosperous Jewish merchant family, Mond studied at the Polytechnic in Cassel and then under the distinguished chemists Hermann Kolbe at Marburg and Bunsen at Heidelberg from 1856. In 1859 he began work as an industrial chemist in various works in Germany and Holland. At this time, Mond was pursuing his method for recovering sulphur from the alkali wastes in the Leblanc soda-making process. Mond came to England in 1862 and five years later settled permanently, in partnership with John Hutchinson \& Co. at Widnes, to perfect his process, although complete success eluded him. He became a naturalized British subject in 1880.

In 1872 Mond became acquainted with Ernest Solvay, the Belgian chemist who developed the ammonia-soda process which finally supplanted the Leblanc process. Mond negotiated the English patent rights and set up the first ammoniasoda plant in England at Winnington in Cheshire, in partnership with John Brunner. After overcoming many difficulties by incessant hard work, the process became a financial success and in 1881 Brunner, Mond \& Co. was formed, for a time the largest alkali works in the world. In 1926 the company merged with others to form Imperial Chemical Industries Ltd (ICI). The firm was one of the first to adopt the eight-hour day and to provide model dwellings and playing fields for its employees.

From 1879 Mond took up the production of ammonia and this led to the Mond producer-gas plant, patented in 1883. The process consisted of passing air and steam over coal and coke at a carefully regulated temperature. Ammonia was generated and, at the same time, so was a cheap and useful producer gas. Mond's major discovery followed the observation in 1889 that carbon monoxide could combine with nickel in its ore at around 60°C to form a gaseous compound, nickel carbonyl. This, on heating to a higher temperature, would then decompose to give pure nickel. Mond followed up this unusual way of producing and purifying a metal and by 1892 had succeeded in setting up a pilot plant to perfect a large-scale process and went on to form the Mond Nickel Company.

Apart from being a successful industrialist, Mond was prominent in scientific circles and played a leading role in the setting up of the Society of Chemical Industry in 1881. The success of his operations earned him great wealth, much of which he donated for learned and charitable purposes. He formed a notable collection of pictures which he bequeathed to the National Gallery.

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SUBJECT AREA: Synthetic materials, Textiles

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Bevan began his working life as a chemist in a soap works at Runcorn, but later studied chemistry at Owens College, Manchester. It was there that he met and formed a friendship with C.F. Cross, with whom he started to work on cellulose. Bevan moved to a paper mill in Scotland but then went south to London, where he and Cross set up a partnership in 1885 as consulting and analytical chemists. Their work was mainly concerned with the industrial utilization of cellulose, and with the problems of the paper and jute industries. Their joint publication, A Text-book of Paper-making, which first appeared in 1888 and went into several editions, became the standard reference and textbook on the subject. The book has a long introductory chapter on cellulose.

In 1892 Cross, Bevan and Clayton Beadle discovered viscose, or sodium cellulose xanthate, and took out the patent which was to be the foundation of the "viscose rayon" industry. They had their own laboratory at Station Avenue, Kew Gardens, where they carried out much work that eventually resulted in viscose: cellulose, usually in the form of wood pulp, was treated first with caustic soda and then with carbon disulphide to form the xanthate, which was then dissolved in a solution of dilute caustic soda to produce a viscous liquid. After being aged, the viscose was extruded through fine holes in a spinneret and coagulated in a dilute acid to regenerate the cellulose as spinnable fibres. At first there was no suggestion of spinning it into fibre, but the hope was to use it for filaments in incandescent electric light bulbs. The sheen on the fibres suggested their possible use in textiles and the term "artificial silk" was later introduced. Cross and Bevan also discovered the acetate "Celanese", which was cellulose triacetate dissolved in acetone and spun in air, but both inventions needed much development before they could be produced commercially.

In 1892 Bevan turned from cellulose to food and drugs and left the partnership to become Public Analyst to Middlesex County Council, a post he held until his death, although in 1895 he and Cross published their important work Cellulose. He was prominent in the affairs of the Society of Public Analysts and became one of its officials.

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SUBJECT AREA: Chemical technology

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Educated in Dublin, Muspratt was apprenticed at the age of 14 to a wholesale chemist and druggist, with whom he remained for three or four years. Muspratt then went in search of the Napoleonic War and found it first in Spain and finally as Second Officer on a naval vessel. Finding the life unpleasantly harsh, he left his ship off Swansea and returned to Dublin around 1814. Soon afterwards, he received an inheritance, much reduced and delayed by litigation in Chancery. He began manufacturing chemicals in a small way and from 1818 set up as a manufacturer of prussiate of potash. In 1823, Muspratt took advantage of the removal of the salt tax to establish the first plant in England for the largescale manufacture of soda by the Leblanc process. His first soda works was on the outskirts of Liverpool, but when this proved inadequate, he established a larger factory at St Helens, Lancashire, where the raw materials lay close at hand. This district has remained an important centre of the British chemical industry ever since. Although the plant was successful commercially, there were environmental problems. The equipment for condensing the hydrochloric acid gas produced were inadequate and this caused extensive damage to local vegetation, so that Muspratt had to contend with legal action lasting from 1832 to 1850. Eventually Muspratt moved his alkali manufacture to Widnes, which also became a great centre for the chemical industry.

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SUBJECT AREA: Chemical technology, Metallurgy

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MacArthur served his apprenticeship in the laboratory of Tennant's Tharsis Sulphur and Copper Company in Glasgow. In 1886 he was appointed Technical Manager of the Tennant-run Cassel Gold Extracting Company. By 1888 he was advocating a treatment scheme in which gold was dissolved from crushed rock by a dilute solution of alkali cyanide and then precipitated onto finely divided zinc. During the next few years, with several assistants, he was extremely active in promoting the new gold-extraction technique in various parts of the world. In 1894 significant sums in royalty payments were received, but by 1897 the patents had been successfully contested; henceforth the Cassel Company concentrated on the production and marketing of the essential sodium cyanide reagent.

MacArthur was Managing Director of the Cassel Company from 1892 to 1897; he resigned as a director in December 1905. In 1907 he created the Antimony Recovery Syndicate, and in 1911 he set up a small plant at Runcorn, Cheshire, to produce radium salts. In 1915 this radium-extraction activity was transferred to Balloch, south of Loch Lomond, where it was used until some years after his death.

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1) Парфюмерия: Стандарты Японии по косметическим ингредиентам

2) Полимеры: Journal of the Society of Chemical Industry

SUBJECT AREA: Chemical technology

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Messel served three years as an apprentice to the chemical manufacturers E.Lucius of Frankfurt before studying chemistry at Zürich, Heidelberg and Tübingen. In 1870 he travelled to England to assist the distinguished chemist Sir Henry Roscoe, but was soon recalled to Germany on the outbreak of the Franco-Prussian War. After hostilities ceased, Messel returned to London to join the firm of manufacturers of sulphuric acid Dunn, Squire \& Company of Stratford, London. The firm amalgamated with Spencer Chapman, and after Messel became its Managing Director in 1878 it was known as Spencer, Chapman \& Messel Ltd.

Messel's principal contribution to chemical technology was the invention of the contact process for the manufacture of sulphuric acid. Earlier processes for making this essential product, now needed in ever-increasing quantities by the new processes for making dyestuffs, fertilizers and explosives, were based on the oxidation of sulphur dioxide by oxides of nitrogen, developed by Joshua Ward and John Roebuck. Attempts to oxidize the dioxide to the trioxide with the oxygen in the air in the presence of a suitable catalyst had so far failed because the catalyst had become "poisoned" and ineffective; Messel avoided this by using highly purified gases. The contact process produced a concentrated form of sulphuric acid called oleum. Until the outbreak of the First World War, Messel's firm was the principal manufacturer, but then the demand rose sharply, so that other firms had to engage in its manufacture. Production thereby increased from 20,000 to 450,000 tons per year.

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SUBJECT AREA: Chemical technology

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It was intended that Weldon should enter his father's factory in Loughborough, but he decided instead to turn to journalism, which he pursued with varying success in London. His Weldon's Register of Facts and Occurrences in Literature, Science, and Art ran for only four years, from 1860 to 1864, but the fashion magazine Weldon's Journal, which he published with his wife, was more successful. Meanwhile Weldon formed an interest in chemistry, although he had no formal training in that subject. He devoted himself to solving one of the great problems of industrial chemistry at that time. The Leblanc process for the manufacture of soda produced large quantities of hydrochloric acid in gas form. By this time, this by-product was being converted, by oxidation with manganese dioxide, to chlorine, which was much used in the textile and paper industries as a bleaching agent. The manganese ended up as manganese chloride, from which it was difficult to convert back to the oxide, for reuse in treating the hydrochloric acid, and it was an expensive substance. Weldon visited the St Helens district of Lancashire, an important centre for the manufacture of soda, to work on the problem. During the three years from 1866 to 1869, he took out six patents for the regeneration of manganese dioxide by treating the manganese chloride with milk of lime and blowing air through it. The Weldon process was quickly adopted and had a notable economic effect: the price of bleaching powder came down by £6 per ton and production went up fourfold.

By the time of his death, nearly all chlorine works in the world used Weldon's process. The distinguished French chemist J.B.A.Dumas said of the process, when presenting Weldon with a gold medal, "every sheet of paper and every yard of calico has been cheapened throughout the world". Weldon played an active part in the founding of the Society of Chemical Industry.

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SUBJECT AREA: Chemical technology, Synthetic materials, Textiles

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He early showed an aptitude for chemistry and in 1853 entered the Royal College of Chemistry as a student under A.W.von Hofmann, the first Professor at the College. By the end of his first year, he had carried out his first piece of chemical research, on the action of cyanogen chloride on phenylamine, which he published in the Journal of the Chemical Society (1857). He became honorary assistant to von Hofmann in 1857; three years previously he had set up his own chemical laboratory at home, where he had discovered the first of the azo dyes, aminoazonapththalene. In 1856 Perkin began work on the synthesis of quinine by oxidizing a salt of allyl toluidine with potassium dichromate. Substituting aniline, he obtained a dark-coloured precipitate which proved to possess dyeing properties: Perkin had discovered the first aniline dye. Upon receiving favourable reports on the new material from manufacturers of dyestuffs, especially Pullars of Perth, Perkin resigned from the College and turned to the commercial exploitation of his discovery. This proved highly successful. From 1858, the dye was manufactured at his Greenford Green works as "Aniline Purple" or "Tyrian Purple". It was later to be referred to by the French as mauve. Perkin's discovery led to the development of the modern dyestuffs industry, supplanting dyes from the traditional vegetable sources. In 1869, he introduced two new methods for making the red dye alizarin, in place of the process that involved the use of the madder plant (Rubia tinctorum). In spite of German competition, he dominated the British market until the end of 1873. After eighteen years in chemical industry, Perkin retired and devoted himself entirely to the pure chemical research which he had been pursuing since the 1850s. He eventually contributed ninety papers to the Chemical Society and further papers to other bodies, including the Royal Society. For example, in 1867 he published his synthesis of unsaturated organic acids, known as "Perkin's synthesis". Other papers followed, on the structure of "Aniline Purple". In 1881 Perkin drew attention to the magnetic-rotatory power of some of the substances he had been dealing with. From then on, he devoted particular attention to the application of this phenomenon to the determination of chemical structure.

Perkin won wide recognition for his discoveries and other contributions to chemistry.

The half-centenary of his great discovery was celebrated in July 1906 and later that year he received a knighthood.

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SUBJECT AREA: Broadcasting, Electronics and information technology, Telecommunications

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Popov, the son of a village priest, received his early education in a seminary, but in 1877 he entered the University of St Petersburg to study mathematics. He graduated with distinction in 1883 and joined the faculty to teach mathematics and physics. Then, increasingly interested in electrical engineering, he became an instructor at the Russian Navy Torpedo School at Krondstadt, near St Petersburg, where he later became a professor. On 7 May 1895 he is said to have transmitted and received Morse code radio signals over a distance of 40 m (130 ft) in a demonstration given at St Petersburg University to the Russian Chemical Society, but in a paper published in January 1896 in the Journal of the Russian Physical and Chemical Society, he in fact described the use of a coherer for recording atmospheric disturbances such as lightning, together with the design of a modified coherer intended for reception at a distance of 5 km (3 miles). Subsequently, on 26 November 1897, after Marconi's own radio-transmission experiments had been publicized, he wrote a letter claiming priority for his discovery to the English-language journal Electrician, in the form of a translated précis of his original paper, but neither the original Russian paper nor the English précis made specific claims of either a receiver or a transmitter as such. However, by 1898 he had certainly developed some form of ship-to-shore radio for the Russian Navy. In 1945, long after the Russian revolution, the communist regime supported his claim to be the inventor of radio, but this is a matter for much debate and the priority of Marconi's claim is generally acknowledged outside the USSR.

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SUBJECT AREA: Agricultural and food technology

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The son of a merchant in the city of his birth, John Christopher had delicate health and required private tuition to overcome the loss of his early years of schooling. At the age of 22 he went to study chemistry at Göttingen University and then worked for a short time for Liebig at Giessen. In 1847 he obtained a post as Analyst and Consulting Chemist at the Agricultural Chemistry Association of Scotland's Edinburgh office, and two years later he became Professor of Chemistry at the Royal Agricultural College in Cirencester, retaining this post until 1862. In 1855 he was appointed Chemist to the Bath and West Agricultural Society, and in that capacity organized lectures and field trials, and in 1857 he also became Consulting Chemist to the Royal Agricultural Society of England. Initially he studied the properties of farmyard manure and also the capacity of the soil to absorb ammonia, potash and sodium. As Consulting Chemist to farmers he analysed feedstuffs and manures; his assessments of artificial manures did much to force improvements in standards. During the 1860s he worked on milk and dairy products. He published the results of his work each year in the Journal of the Royal Agricultural Society of England. In 1877 he became involved in the field trials initiated and funded by the Duke of Bedford on his Woburn farm, and he continued his association with this venture until his death.

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See also: Voelcker, John Augustus

SUBJECT AREA: Chemical technology, Synthetic materials, Textiles

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Cross was educated at the universities of London, Zurich and Manchester. It was at Owens College, Manchester, that Cross first met E.J. Bevan and where these two first worked together on the nature of cellulose. After gaining some industrial experience, Cross joined Bevan to set up a partnership in London as analytical and consulting chemists, specializing in the chemistry and technology of cellulose and lignin. They were at the Jodrell laboratory, Kew Gardens, for a time and then set up their own laboratory at Station Avenue, Kew Gardens. In 1888, the first edition of their joint publication A Textbook of Paper-making, appeared. It went into several editions and became the standard reference and textbook on the subject. The long introductory chapter is a discourse on cellulose.

In 1892, Cross, Bevan and Clayton Beadle took out their historic patent on the solution and regeneration of cellulose. The modern artificial-fibre industry stems from this patent. They made their discovery at New Court, Carey Street, London: wood-pulp (or another cheap form of cellulose) was dissolved in a mixture of carbon disulphide and aqueous alkali to produce sodium xanthate. After maturing, it was squirted through fine holes into dilute acid, which set the liquid to give spinnable fibres of "viscose". However, it was many years before the process became a commercial operation, partly because the use of a natural raw material such as wood involved variations in chemical content and each batch might react differently. At first it was thought that viscose might be suitable for incandescent lamp filaments, and C.H.Stearn, a collaborator with Cross, continued to investigate this possibility, but the sheen on the fibres suggested that viscose might be made into artificial silk. The original Viscose Spinning Syndicate was formed in 1894 and a place was rented at Erith in Kent. However, it was not until some skeins of artificial silk (a term to which Cross himself objected) were displayed in Paris that textile manufacturers began to take an interest in it. It was then that Courtaulds decided to investigate this new fibre, although it was not until 1904 that they bought the English patents and developed the first artificial silk that was later called "rayon". Cross was also concerned with the development of viscose films and of cellulose acetate, which became a rival to rayon in the form of "Celanese". He retained his interest in the paper industry and in publishing, in 1895 again collaborating with Bevan and publishing a book on Cellulose and other technical articles. He was a cultured man and a good musician. He was elected a Fellow of the Royal Society in 1917.

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SUBJECT AREA: Electricity

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With an early bias towards science, Daniell's interest in chemistry was formed when he joined a relative's sugar-refining business. He formed a lifelong friendship with W.T.Brande, Professor of Chemistry at the Royal Institution, and together they revived the journal of the Royal Institution, to which Daniell submitted many of his early papers on chemical subjects. He made many contributions to the science of meteorology and in 1820 invented a hydrometer, which became widely used and gave precision to the measurement of atmospheric moisture. As one of the originators of the Society for Promoting Useful Knowledge, Daniell edited several of its early publications. His work on crystallization established his reputation as a chemist and in 1831 he was appointed the first Professor of Chemistry at King's College, London, where he was largely responsible for establishing its department of applied science. He was also involved in the Chemical Society of London and served as its Vice-President. At King's College he began the research into current electricity with which his name is particularly associated. His investigations into the zinc-copper cell revealed that the rapid decline in power was due to hydrogen gas being liberated at the positive electrode. Daniell's cell, invented in 1836, employed a zinc electrode in dilute sulphuric acid and a copper electrode in a solution of copper sulphate, the electrodes being separated by a porous membrane, typically an unglazed earthenware pot. He was awarded the Copley Medal of the Royal Society for his invention which avoided the "polarization" of the simple cell and provided a further source of current for electrical research and for commercial applications such as electroplating. Although the high internal resistance of the Daniell cell limited the current and the potential was only 1.1 volts, the voltage was so unchanging that it was used as a reference standard until the 1870s, when J. Lattimer Clark devised an even more stable cell.

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SUBJECT AREA: Textiles

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Mercer began work at the age of 9 as a bobbinwinder and then a hand-loom weaver. He had no formal education in chemistry but taught himself and revealed remarkable ability in both theoretical and applied aspects of the subject. He became the acknowledged "father of textile chemistry" and the Royal Society elected him Fellow in 1850. His name is remembered in connection with the lustrous "mercerized" cotton which, although not developed commercially until 1890, arose from his discovery, c. 1844, of the effect of caustic soda on cotton linters. He also discovered that cotton could be dissolved in a solution of copper oxide in ammonia, a phenomenon later exploited in the manufacture of artificial silk. As a youth, Mercer experimented at home with dyeing processes and soon acquired sufficient skill to set up as an independent dyer. Most of his working life was, however, spent with the calico-printing firm of Oakenshaw Print Works in which he eventually became a partner, and it was there that most of his experimental work was done. The association was a very appropriate one, for it was a member of this firm's staff who first recognized Mercer's potential talent and took the trouble in his spare time to teach him reading, writing and arithmetic. Mercer developed manganese-bronze colours and researched into catalysis and the ferrocyanides. Among his innovations was the chlorination of wool in order to make it print as easily as cotton. It was many years later that it was realized that this treatment also conferred valuable shrink-resisting qualities. Becoming interested in photochemistry, he devised processes for photographic printing on fabric. Queen Victoria was presented with a handkerchief printed in this way when she visited the Great Exhibition of 1851, of which Mercer was a juror. A photograph of Mercer himself on cloth is preserved in the Museum of Science and Industry in Manchester. He presented papers to the British Association and was a member of the Chemical Society.

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SUBJECT AREA: Agricultural and food technology

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John Augustus Voelcker, as the son of Dr John Christopher Voelcker, grew up in an atmosphere of scientific agriculture and would have had contact with the leading agriculturists of the day. He was educated at University College School and then University College, London, where he obtained both a BA and a BSc Following in his father's footsteps, he studied for his PhD at Giessen University in Germany. At college he enjoyed athletics, an interest he was to pursue for the rest of his life. He decided to take up agricultural chemistry and was to succeed to all the public offices once held by his father, from whom he also took over the directorship of Woburn Farm. The experimental farm had been started in 1876 and was used to study the residual effects of chemicals in the soil. The results of these studies were used as the basis for compensation awards to tenant farmers giving up their farms. Voelcker broadened the range of studies to include trace elements in the soil, but by 1921 the Royal Agricultural Society of England had decided to give up the farm. This was a blow to Voelcker and occurred just before experiments elsewhere highlighted the importance of these elements to healthy plant growth. He continued the research at his own expense until the Rothampsted Experimental Station took over the farm in 1926. Aside from his achievements in Britain, Voelcker undertook a study tour of India in 1890, the report on which led to the appointment of an Agricultural Chemist, and the establishment of a scientific service for the Indian subcontinent.

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SUBJECT AREA: Chemical technology

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Bunsen's father was Librarian and Professor of Linguistics at Göttingen University and Bunsen himself studied chemistry there. Obtaining his doctorate at the age of only 19, he travelled widely, meeting some of the leading chemists of the day and visiting many engineering works. On his return he held various academic posts, finally as Professor of Chemistry at Heidelberg in 1852, a post he held until his retirement in 1889.

During 1837–41 Bunsen studied a series of compounds shown to contain the cacodyl (CH3)2As-group or radical. The elucidation of the structure of these compounds gave support to the radical theory in organic chemistry and earned him fame, but it also cost him the sight of an eye and other ill effects resulting from these dangerous and evil-smelling substances. With the chemist Gustav Robert Kirchhoff (1824–87), Bunsen pioneered the use of spectroscopy in chemical analysis from 1859, and with its aid he discovered the elements caesium and rubidium. He developed the Bunsen cell, a zinc-carbon primary cell, with which he isolated a number of alkali and other metals by electrodeposition from solution or electrolysis of fused chlorides.

Bunsen's main work was in chemical analysis, in the course of which he devised some important laboratory equipment, such as a filter pump. The celebrated Bunsen gas burner was probably devised by his technician Peter Desdega. During 1838–44 Bunsen applied his methods of gas analysis to the study of the gases produced by blast furnaces for the production of cast iron. He demonstrated that no less than 80 per cent of the heat was lost during smelting, and that valuable gaseous by-products, such as ammonia, were also lost. Lyon Playfair in England was working along similar lines, and in 1848 the two men issued a paper, "On the gases evolved from iron furnaces", to draw attention to these drawbacks.

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SUBJECT AREA: Chemical technology

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Haber's father was a manufacturer of dyestuffs, so he studied organic chemistry at Berlin and Heidelberg universities to equip him to enter his father's firm. But his interest turned to physical chemistry and remained there throughout his life. He became Assistant at the Technische Hochschule in Karlsruhe in 1894; his first work there was on pyrolysis and electrochemistry, and he published his Grundrisse der technischen Electrochemie in 1898. Haber became famous for thorough and illuminating theoretical studies in areas of growing practical importance. He rose through the academic ranks and was appointed a full professor in 1906. In 1912 he was also appointed Director of the Institute of Physical Chemistry and Electrochemistry at Dahlem, outside Berlin.

Early in the twentieth century Haber invented a process for the synthesis of ammonia. The English chemist and physicist Sir William Crookes (1832–1919) had warned of the danger of mass hunger because the deposits of Chilean nitrate were becoming exhausted and nitrogenous fertilizers would not suffice for the world's growing population. A solution lay in the use of the nitrogen in the air, and the efforts of chemists centred on ways of converting it to usable nitrate. Haber was aware of contemporary work on the fixation of nitrogen by the cyanamide and arc processes, but in 1904 he turned to the study of ammonia formation from its elements, nitrogen and hydrogen. During 1907–9 Haber found that the yield of ammonia reached an industrially viable level if the reaction took place under a pressure of 150–200 atmospheres and a temperature of 600°C (1,112° F) in the presence of a suitable catalyst—first osmium, later uranium. He devised an apparatus in which a mixture of the gases was pumped through a converter, in which the ammonia formed was withdrawn while the unchanged gases were recirculated. By 1913, Haber's collaborator, Carl Bosch had succeeded in raising this laboratory process to the industrial scale. It was the first successful high-pressure industrial chemical process, and solved the nitrogen problem. The outbreak of the First World War directed the work of the institute in Dahlem to military purposes, and Haber was placed in charge of chemical warfare. In this capacity, he developed poisonous gases as well as the means of defence against them, such as gas masks. The synthetic-ammonia process was diverted to produce nitric acid for explosives. The great benefits and achievement of the Haber-Bosch process were recognized by the award in 1919 of the Nobel Prize in Chemistry, but on account of Haber's association with chemical warfare, British, French and American scientists denounced the award; this only added to the sense of bitterness he already felt at his country's defeat in the war. He concentrated on the theoretical studies for which he was renowned, in particular on pyrolysis and autoxidation, and both the Karlsruhe and the Dahlem laboratories became international centres for discussion and research in physical chemistry.

With the Nazi takeover in 1933, Haber found that, as a Jew, he was relegated to second-class status. He did not see why he should appoint staff on account of their grandmothers instead of their ability, so he resigned his posts and went into exile. For some months he accepted hospitality in Cambridge, but he was on his way to a new post in what is now Israel when he died suddenly in Basel, Switzerland.

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SUBJECT AREA: Chemical technology

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Young's early education took place in the evenings, after the day's work in his father's joinery. From 1830 he studied chemistry at the evening classes in Glasgow given by the distinguished Scottish chemist Thomas Graham (1805–69) and soon afterwards became Graham's assistant. When Graham moved to University College London in 1837, Young accompanied him.

From 1839 he was employed in the chemical industry, first with James Muspratt at St Helens, Lancashire, and from 1843 with Tennant \& Company in Manchester. In 1848 his attention was drawn to an oil seepage in a mine at Alfreton, Derbyshire, of some 300 gallons per day; he set up his own works there to extract an oil that could be used for lighting and lubrication. When this source of oil was exhausted, three years later, Young moved to Lothian in Scotland. By distillation, he extracted oil from the oil-shale deposits there and thus founded the Scottish oil-shale industry: he obtained a high yield of paraffin oil for lighting and heating, and was a pioneer in the use of chemical methods in extracting and treating oil. In 1866 he disposed of his company for no less than £400,000. Young's other activities included measuring the speed of light by Fizeau's method and giving financial support to the expeditions of David Livingstone, who had been a fellow student in Glasgow.

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SUBJECT AREA: Electricity, Photography, film and optics

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At the age of 14 Swan was apprenticed to a Sunderland firm of druggists, later joining John Mawson who had opened a pharmacy in Newcastle. While in Sunderland Swan attended lectures at the Athenaeum, at one of which W.E. Staite exhibited electric-arc and incandescent lighting. The impression made on Swan prompted him to conduct experiments that led to his demonstration of a practical working lamp in 1879. As early as 1848 he was experimenting with carbon as a lamp filament, and by 1869 he had mounted a strip of carbon in a vessel exhausted of air as completely as was then possible; however, because of residual air, the filament quickly failed.

Discouraged by the cost of current from primary batteries and the difficulty of achieving a good vacuum, Swan began to devote much of his attention to photography. With Mawson's support the pharmacy was expanded to include a photographic business. Swan's interest in making permanent photographic records led him to patent the carbon process in 1864 and he discovered how to make a sensitive dry plate in place of the inconvenient wet collodian process hitherto in use. He followed this success with the invention of bromide paper, the subject of a British patent in 1879.

Swan resumed his interest in electric lighting. Sprengel's invention of the mercury pump in 1865 provided Swan with the means of obtaining the high vacuum he needed to produce a satisfactory lamp. Swan adopted a technique which was to become an essential feature in vacuum physics: continuing to heat the filament during the exhaustion process allowed the removal of absorbed gases. The inventions of Gramme, Siemens and Brush provided the source of electrical power at reasonable cost needed to make the incandescent lamp of practical service. Swan exhibited his lamp at a meeting in December 1878 of the Newcastle Chemical Society and again the following year before an audience of 700 at the Newcastle Literary and Philosophical Society. Swan's failure to patent his invention immediately was a tactical error as in November 1879 Edison was granted a British patent for his original lamp, which, however, did not go into production. Parchmentized thread was used in Swan's first commercial lamps, a material soon superseded by the regenerated cellulose filament that he developed. The cellulose filament was made by extruding a solution of nitro-cellulose in acetic acid through a die under pressure into a coagulating fluid, and was used until the ultimate obsolescence of the carbon-filament lamp. Regenerated cellulose became the first synthetic fibre, the further development and exploitation of which he left to others, the patent rights for the process being sold to Courtaulds.

Swan also devised a modification of Planté's secondary battery in which the active material was compressed into a cellular lead plate. This has remained the central principle of all improvements in secondary cells, greatly increasing the storage capacity for a given weight.

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SUBJECT AREA: Metallurgy

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Wollaston qualified in medicine at Cambridge University but gave up his practice in 1800 to devote himself to chemistry and metallurgy, funded from the profits from making malleable platinum. In partnership with Smithson Tennant, a friend from his Cambridge days, he worked on the extraction of platinum by dissolving it in aqua regia. In 1802 he found that in addition to platinum the solution contained a new metal, which he named palladium. Two years later he identified another new metal, rhodium.

Wollaston developed a method of forming platinum by means of powder metallurgy and was the first to produce malleable and ductile platinum on a commercial scale. He produced platinum vessels for sulphuric acid manufacture and scientific apparatus such as crucibles. He devised an elegant method for forming fine platinum wire. He also applied his inventive talents to improving scientific apparatus, including the sextant and microscope and a reflecting goniometer for measuring crystal angles. In 1807 he was appointed Joint Secretary of the Royal Society with Sir Humphry Davy, which entailed a heavy workload and required them to referee all the papers submitted to the Society for publication.

Wollaston's output of platinum began to decline after 1822. Due to ill health he ceased business operations in 1828 and at last made public the details of his secret platinum fabrication process. It was fully described in the Bakerian Lecture he delivered to the Royal Society on 28 November 1828, shortly before his death.

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