Henri II

[ɑ̃ri] nom propre

[roi de France] Henri

[roi d'Angleterre] Henry

voir aussi link=cinq cinq

Henri Becquerel, Antoine Henri Becquerel.

Henri Bergson, Henri Louis Bergson.

Henri Matisse, Henri Emile Benoit Matisse.

Henri Rousseau, Le Douanier Rousseau.

SUBJECT AREA: Metallurgy

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Deville was the son of a prosperous shipowner with diplomatic duties in the Virgin Islands. With his elder brother Charles, who later became a distinguished physicist, he was sent to Paris to be educated. He took his degree in medicine in 1843, but before that he had shown an interest in chemistry, due particularly to the lectures of Thenard. Two years later, with Thenard's influence, he was appointed Professor of Chemistry at Besançon. In 1851 he was able to return to Paris as Professor at the Ecole Normale Supérieure. He remained there for the rest of his working life, greatly improving the standard of teaching, and his laboratory became one of the great research centres of Europe. His first chemical work had been in organic chemistry, but he then turned to inorganic chemistry, specifically to improve methods of producing the new and little-known metal aluminium. Essentially, the process consisted of forming sodium aluminium trichloride and reducing it with sodium to metallic aluminium. He obtained sodium in sufficient quantity by reducing sodium carbonate with carbon. In 1855 he exhibited specimens of the metal at the Paris Exhibition, and the same year Napoleon III asked to see them, with a view to using it for breastplates for the Army and for spoons and forks for State banquets. With the resulting government support, he set up a pilot plant at Jarvel to develop the process, and then set up a small company, the Société d'Aluminium at Nan terre. This raised the output of this attractive and useful metal, so it could be used more widely than for the jewellery to which it had hitherto been restricted. Large-scale applications, however, had to await the electrolytic process that began to supersede Deville's in the 1890s. Deville extended his sodium reduction method to produce silicon, boron and the light metals magnesium and titanium. His investigations into the metallurgy of platinum revolutionized the industry and led in 1872 to his being asked to make the platinum-iridium (90–10) alloy for the standard kilogram and metre. Deville later carried out important work in high-temperature chemistry. He grieved much at the death of his brother Charles in 1876, and his retirement was forced by declining health in 1880; he did not survive for long.

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SUBJECT AREA: Aerospace

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Throughout the history of aviation there have been many attempts to produce a cheap and simple aeroplane for "the man in the street". The tiny Demoiselle built by Alberto Santos- Dumont in 1909 or the de Havilland Moth of 1925 are good examples, but the one which very nearly achieved this aim was Henri Mignet's Flying Flea of 1933. Mignet was a self-taught designer of light aircraft, which often incorporated his unorthodox ideas. His Pou-du-Ciel ("Sky Louse" or "Flying Flea") was unorthodox. The materials used in construction were conventional wood and fabric, but the control system departed from the usual wing plus tailplane (with elevators). The Flea had two wings in tandem. The rear wing was fixed, while the forward wing was hinged to allow the angle of incidence, and hence its lift, to be increased or decreased. Reducing the forward wing's lift would cause the Flea to dive. After Mignet's first flight, on 6 September 1933, and the publication of his book Le Sport de l'air, which explains how to build a Poudu-Ciel, a Pou-building craze started in France. Mignet's book was translated into English and 6,000 copies were sold in a month. During 1935 the craze spread to Britain, where a Flying Flea could be built for £50–£90, including the engine. After several fatal crashes, the aircraft was banned in 1936. A design fault in the control system was to blame, and although this was remedied the wave of popular enthusiasm vanished. Mignet continued to design light aircraft and during the Second World War he was working on a Pou- Maquis for use by the French Resistance but the war ended before the aircraft was ready. During the post-war years a series of Flying Flea derivatives appeared, but their numbers were small. However, the home-build movement in general has grown in recent years, a fact which would have pleased Henri Mignet, the "Patron Saint of Homebuilders".

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SUBJECT AREA: Aerospace

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The parents of Henri and Maurice Farman were British subjects living in Paris, but their sons lived all their lives in France and became French citizens. As young men, both became involved in cycle and automobile racing. Henri (or Henry—he used both versions) turned his attention to aviation in 1907 when he bought a biplane from Gabriel Voisin. Within a short time he had established himself as one of the leading pilots in Europe, with many record-breaking flights to his credit. Farman modified the Voisin with his own improvements, including ailerons, and then in 1909 he designed the first Farman biplane. This became the most popular biplane in Europe from the autumn of 1909 until well into 1911 and is one of the classic aeroplanes of history. Meanwhile, Maurice Farman had also begun to design and build biplanes; his first design of 1909 was not a great success but from it evolved two robust biplanes nicknamed the "Longhorn" and the "Shorthorn", so called because of their undercarriage skids. In 1912 the brothers joined forces and set up a very large factory at Billancourt. The "Longhorn" and "Shorthorn" became the standard training aircraft in France and Britain during the early years of the First World War. The Farman brothers went on to produce a number of other wartime designs, including a large bomber. After the war the Farmans produced a series of large airliners which played a key role in establishing France as a major airline operator. Most famous of these was the Goliath, a twin-engined biplane capable of carrying up to twelve passengers. This was produced from 1918 to 1929 and was used by many airlines, including the Farman Line. The brothers retired when their company was nationalized in 1937.

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See: Le Chatelier, Henri Louis

SUBJECT AREA: Aerospace, Steam and internal combustion engines

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Giffard entered the works of the Western Railway of France at the age of 16 but became absorbed by the problem of steam-powered aerial navigation. He proposed a steam-powered helicopter in 1847, but he then turned his attention to an airship. He designed a lightweight coke-burning, single-cylinder steam engine and boiler which produced just over 3 hp (2.2 kW) and mounted it below a cigar-shaped gas bag 44 m (144 ft) in length. A triangular rudder was fitted at the rear to control the direction of flight. On 24 September 1852 Giffard took off from Paris and, at a steady 8 km/h (5 mph), he travelled 28 km (17 miles) to Trappes. This can be claimed to be the first steerable lighter-than-air craft, but with a top speed of only 8 km/h (5 mph) even a modest headwind would have reduced the forward speed to nil (or even negative). Giffard built a second airship, which crashed in 1855, slightly injuring Giffard and his companion; a third airship was planned with a very large gas bag in order to lift the inherently heavy steam engine and boiler, but this was never built. His airships were inflated by coal gas and refusal by the gas company to provide further supplies brought these promising experiments to a premature end.

As a draughtsman Giffard had the opportunity to travel on locomotives and he observed the inadequacies of the feed pumps then used to supply boiler feedwater. To overcome these problems he invented the injector with its series of three cones: in the first cone (convergent), steam at or below boiler pressure becomes a high-velocity jet; in the second (also convergent), it combines with feedwater to condense and impart high velocity to it; and in the third (divergent), that velocity is converted into pressure sufficient to overcome the pressure of steam in the boiler. The injector, patented by Giffard, was quickly adopted by railways everywhere, and the royalties provided him with funds to finance further experiments in aviation. These took the form of tethered hydrogen-inflated balloons of successively larger size. At the Paris Exposition of 1878 one of these balloons carried fifty-two passengers on each tethered "flight". The height of the balloon was controlled by a cable attached to a huge steam-powered winch, and by the end of the fair 1,033 ascents had been made and 35,000 passengers had seen Paris from the air. This, and similar balloons, greatly widened the public's interest in aeronautics. Sadly, after becoming blind, Giffard committed suicide; however, he died a rich man and bequeathed large sums of money to the State for humanitarian an scientific purposes.

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PJGR / JDS

SUBJECT AREA: Metallurgy

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The son of a distinguished engineer, Le Chatelier entered the Ecole Polytechnique in 1869: after graduating in the Faculty of Mines, he was appointed Professor at the Ecole Supérieure des Mines in 1877. After assisting Deville with the purification of bauxite in unsuccessful attempts to obtain aluminium in useful quantities, Le Chatelier's work covered a wide range of topics and he gave much attention to the driving forces of chemical reactions. Between 1879 and 1882 he studied the mechanisms of explosions in mines, and his doctorate in 1882 was concerned with the chemistry and properties of hydraulic cements. The dehydration of such materials was studied by thermal analysis and dilatometry. Accurate temperature measurement was crucial and his work on the stability of thermocouples, begun in 1886, soon established the superiority of rhodium-platinum alloys for high-temperature measurement. The most stable combination, pure platinum coupled with a 10 per cent rhodium platinum positive limb, became known as Le Chatelier couple and was in general use throughout the industrial world until c. 1922. For applications where thermocouples could not be used, Le Chatelier also developed the first practical optical pyrometer. From hydraulic cements he moved on to refractory and other ceramic materials which were also studied by thermal analysis and dilatometry. By 1888 he was systematically applying such techniques to metals and alloys. Le Chatelier, together with Osmond, Worth, Genet and Charpy, was a leading member of that group of French investigators who established the new science of physical metallurgy between 1888 and 1900. Le Chatelier was determining the recalescence points in steels in 1888 and was among the first to study intermetallic compounds in a systematic manner. To facilitate such work he introduced the inverted microscope, upon which metallographers still depend for the routine examination of polished and etched metallurgical specimens under incident light. The principle of mobile equilibrium, developed independently by Le Chatelier in 1885 and F.Braun in 1886, stated that if one parameter in an equilibrium situation changed, the equilibrium point of the system would move in a direction which tended to reduce the effect of this change. This provided a useful qualitative working tool for the experimentalists, and was soon used with great effect by Haber in his work on the synthesis of ammonia.

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SUBJECT AREA: Chemical technology

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His family, of modest means, moved in 1864 to Meaux, where he attended the municipal college; he returned to Paris before completing his education and apprenticed himself to a pharmacist. In 1872 he began work as a laboratory assistant at the Musée d'Histoire Naturelle, while continuing studies in chemistry. He qualified as a pharmacist at the Ecole Supérieure de Pharmacie in 1879, and by this time he had decided that his main interest was inorganic chemistry. His early investigations concerned the oxides of iron and related metals; his work attracted the favourable attention of Sainte-Claire Deville and was the subject of his doctoral thesis. In 1882 Moissan married Leonie Lugan, whose father provided generous financial support, enabling him to pursue his researches with greater freedom and security. He became, successively, Professor of Toxicology at the Ecole in 1886 and of Inorganic Chemistry in 1899. In 1884 Moissan began both his investigation of the compounds of fluorine and his attempts to isolate the highly reactive element itself. Previous attempts by chemists had ended in failure and sometimes injury. Moissan's health, too, was affected, but in June 1886 he succeeded in isolating fluorine by electrolysing potassium fluoride in hydrogen fluoride at −50°C (−58°F) in platinum apparatus. He was then able to prepare further compounds of fluorine, some of technological importance, such as carbon tetrafluoride. At the same time, Moissan turned his attention to the making of artificial diamonds. To achieve this, he devised his celebrated electric-arc furnace; this was first demonstrated in December 1892 and consisted of two lime blocks placed one above the other, with a cavity for a crucible and two grooves for carbon electrodes, and could attain a temperature of 3,500°C (6,332°F). It seemed at first that he had succeeded in making diamonds, but this attempt is now regarded as a failure. Nevertheless, with the aid of his furnace he was able to produce and study many substances of technological importance, including refractory oxides, borides and carbides, and such metals as manganese, chromium, uranium, tungsten, vanadium, molybdenum, titanium and zirconium; many of these materials had useful applications in the chemical and metallurgical industries (e.g. calcium carbide became the main source of acetylene).

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See: Deville, Henri Etienne Sainte-Claire