accurate+reading

SUBJECT AREA: Photography, film and optics

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Fizeau's interest in photography was comparatively brief, but during this period he was at the forefront of French attempts to explore and exploit the potential of the recently announced daguerreotype process (see Daguerre). Fizeau is best remembered for his introduction in August 1840 of the practice of gold-toning daguerreotypes. This improvement not only helped protect the delicate surface of the plate from abrasion and tarnishing, but also enhanced the quality of the image. The technique was not patented and was immediately adopted by all daguerreotypists. Between 1839 and 1841, in association with Alfred Donné, Fizeau conducted experiments with the aim of converting daguerreotypes into printing plates. Prints from two of his plates were published in 1842, but the technique was never widely practised. In association with J.B.Léon Foucault, Fizeau discovered the reciprocity failure of daguerreotypes, and the same partnership produced what were probably the first daguerreotypes of the sun. Fizeau is best known in physics for making the first accurate determination of the speed of light, in 1849.

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SUBJECT AREA: Medical technology

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The younger son of a landed Midlands family, Floyer embarked on medical studies at Oxford at the age of 15 and graduated in 1674. He returned to Lichfield where he resided and practised, as well as being acquainted with the family of Samuel Johnson, for the remainder of a long life. Described by a later biographer as "fantastic, whimsical, pretentious, research-minded and nebulous", he none the less, as his various medical writings testify, became a pioneer in several fields of medical endeavour. It seems likely that he was well aware of the teachings of Sanctorius in relation to measurement in medicine and he probably had a copy of Sanctorius's weighing-machine made and put to use in Lichfield.

He also embarked on extensive studies relating to pulse, respiration rate, temperature, barometric readings and even latitude. Initially he used the minute hand of a pendulum clock or a navigational minute glass. He then commissioned from Samuel Watson, a London watch-and clockmaker, a physicians' pulse watch incorporating a second-hand and a stop mechanism. In 1707 and 1710 he published a massive work, dedicated to Queen Anne, that emphasized the value of the accurate measurement of pulse rates in health and disease.

His other interests included studies of blood pressure, asthma, and the medical value of cold bathing. It is of interest that it was at his suggestion that the young Samuel Johnson was taken to London to receive the Royal Touch, from Queen Anne, for scrofula.

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SUBJECT AREA: Ports and shipping

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Froude was educated at a preparatory school at Buckfastleigh, and then at Westminster School, London, before entering Oriel College, Oxford, to read mathematics and classics. Between 1836 and 1838 he served as a pupil civil engineer, and then he joined the staff of Isambard Kingdom Brunel on various railway engineering projects in southern England, including the South Devon Atmospheric Railway. He retired from professional work in 1846 and lived with his invalid father at Dartington Parsonage. The next twenty years, while apparently unproductive, were important to Froude as he concentrated his mind on difficult mathematical and scientific problems. Froude married in 1839 and had five children, one of whom, Robert Edmund Froude (1846–1924), was to succeed him in later years in his research work for the Admiralty. Following the death of his father, Froude moved to Paignton, and there commenced his studies on the resistance of solid bodies moving through fluids. Initially these were with hulls towed through a house roof storage tank by wires taken over a pulley and attached to falling weights, but the work became more sophisticated and was conducted on ponds and the open water of a creek near Dartmouth. Froude published work on the rolling of ships in the second volume of the Transactions of the then new Institution of Naval Architects and through this became acquainted with Sir Edward Reed. This led in 1870 to the Admiralty's offer of £2,000 towards the cost of an experimental tank for ship models at Torquay. The tank was completed in 1872 and tests were carried out on the model of HMS Greyhound following full-scale towing trials which had commenced on the actual ship the previous year. From this Froude enunciated his Law of Comparisons, which defines the rules concerning the relationship of the power required to move geometrically similar floating bodies across fluids. It enabled naval architects to predict, from a study of a much less expensive and smaller model, the resistance to motion and the power required to move a full-size ship. The work in the tank led Froude to design a model-cutting machine, dynamometers and machinery for the accurate ruling of graph paper. Froude's work, and later that of his son, was prodigious and covered many fields of ship design, including powering, propulsion, rolling, steering and stability. In only six years he had stamped his academic authority on the new science of hydrodynamics, served on many national committees and corresponded with fellow researchers throughout the world. His health suffered and he sailed for South Africa to recuperate, but he contracted dysentery and died at Simonstown. He will be remembered for all time as one of the greatest "fathers" of naval architecture.

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SUBJECT AREA: Electronics and information technology

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George B.Grant was descended from families who came from Britain in the seventeenth century and was educated at the Bridgton (Maine) Academy, the Chandler Scientific School of Dartmouth College and the Lawrence Scientific School of Harvard College, where he graduated with the degree of BS in 1873. As an undergraduate he became interested in calculating machines, and his paper "On a new difference engine" was published in the American Journal of Science in August 1871. He also took out his first patents relating to calculating machines in 1872 and 1873. A machine of his design known as "Grant's Difference Engine" was exhibited at the Centennial Exposition in Philadelphia in 1876. Similar machines were also manufactured for sale; being sturdy and reliable, they did much to break down the prejudice against the use of calculating machines in business. Grant's work on calculating machines led to a requirement for accurate gears, so he established a machine shop for gear cutting at Charlestown, Massachusetts. He later moved the business to Boston and incorporated it under the name of Grant's Gear Works Inc., and continued to control it until his death. He also established two other gear-cutting shops, the Philadelphia Gear Works Inc., which he disposed of in 1911, and the Cleveland Gear Works Inc., which he also disposed of after a few years. Grant's commercial success was in connection with gear cutting and in this field he obtained several patents and contributed articles to the American Machinist. However, he continued to take an interest in calculating machines and in his later years carried out experimental work on their development.

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SUBJECT AREA: Horology, Metallurgy

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Guillaume came from a family of clock-and watchmakers. He was educated at the Gymnasium in Neuchâtel and at Zurich Polytechnic, from which he received his doctorate in 1883 for a thesis on electrolytic capacitors. In the same year he joined the International Bureau of Weights and Measures at Sèvres in France, where he was to spend the rest of his working life. He retired as Director in 1936. At the bureau he was involved in distributing the national standards of the metre to countries subscribing to the General Conference on Weights and Measures that had been held in 1889. This made him aware of the crucial effect of thermal expansion on the lengths of the standards and he was prompted to look for alternative materials that would be less costly than the platinum alloys which had been used. While studying nickel steels he made the surprising discovery that the thermal expansion of certain alloy compositions was less than that of the constituent metals. This led to the development of a steel containing about 36 per cent nickel that had a very low thermal coefficient of expansion. This alloy was subsequently named "invar", an abbreviation of invariable. It was well known that changes in temperature affected the timekeeping of clocks by altering the length of the pendulum, and various attempts had been made to overcome this defect, most notably the mercury-compensated pendulum of Graham and the gridiron pendulum of Harrison. However, an invar pendulum offered a simpler and more effective method of temperature compensation and was used almost exclusively for pendulum clocks of the highest precision.

Changes in temperature can also affect the timekeeping of watches and chronometers, but this is due mainly to changes in the elasticity or stiffness of the balance spring rather than to changes in the size of the balance itself. To compensate for this effect Guillaume developed another more complex nickel alloy, "elinvar" (elasticity invariable), whose elasticity remained almost constant with changes in temperature. This had two practical consequences: the construction of watches could be simplified (by using monometallic balances) and more accurate chronometers could be made.

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See also: Le Roy, Pierre

SUBJECT AREA: Canals, Civil engineering

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First, from 1262, he was engaged in hydraulic-engineering works for Kublai Khan. He began astronomical and calendrical investigations in 1276, and became the greatest astronomer of the Yuan dynasty. He perfected interpolation formulae (a method of finite differences) and was the founder of the study of spherical trigonometry in China; this was applied to the circles of the heavenly sphere. He planned the Ji Zhou, the summit section of the Grand Canal through the Shandong foothills, in 1283. Although the canal had to await further improvement before it could become fully effective, it was nevertheless the world's first successful entirely artificial summit canal.

Guo Shoujing was responsible for the construction of the Tong Hui He (Channel of Communicating Grace) canal with twenty lock gates in 1293, in addition to the overhaul of the entire Grand Canal. He constructed a number of devices, including 40 ft (12 m) gnomons in 1276, with which he made some of the most accurate measurements of the sun's solstitial shadows, the results of which were collected in a book that is now lost. Between 1276 and 1279 he also constructed at least one water-driven mechanical escapement clock with sophisticated jack work, and the Beijing observatory and its equipment.

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SUBJECT AREA: Mining and extraction technology

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Hair is best known for the folio volume A Series of Views of the Collieries in the Counties of Northumberland and Durham, published in 1839. This is a volume of engravings after watercolours by T.H.Hair which show in its forty-two pictures particular collieries and details of the workings. The accompanying text by M.Ross describes the pictures and the activities of the various collieries in considerable detail. One of Hair's most famous paintings is "Hartley Colliery after the Disaster" (1869). T.H.Hair's paintings and his book are important for they give an accurate picture of industrial Northumberland and Durham in the middle of the nineteenth century.

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SUBJECT AREA: Horology, Ports and shipping

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John Harrison was the son of a carpenter and was brought up to that trade. He was largely self-taught and learned mechanics from a copy of Nicholas Saunderson's lectures that had been lent to him. With the assistance of his younger brother, James, he built a series of unconventional clocks, mainly of wood. He was always concerned to reduce friction, without using oil, and this influenced the design of his "grasshopper" escapement. He also invented the "gridiron" compensation pendulum, which depended on the differential expansion of brass and steel. The excellent performance of his regulator clocks, which incorporated these devices, convinced him that they could also be used in a sea dock to compete for the longitude prize. In 1714 the Government had offered a prize of £20,000 for a method of determining longitude at sea to within half a degree after a voyage to the West Indies. In theory the longitude could be found by carrying an accurate timepiece that would indicate the time at a known longitude, but the requirements of the Act were very exacting. The timepiece would have to have a cumulative error of no more than two minutes after a voyage lasting six weeks.

In 1730 Harrison went to London with his proposal for a sea clock, supported by examples of his grasshopper escapement and his gridiron pendulum. His proposal received sufficient encouragement and financial support, from George Graham and others, to enable him to return to Barrow and construct his first sea clock, which he completed five years later. This was a large and complicated machine that was made out of brass but retained the wooden wheelwork and the grasshopper escapement of the regulator clocks. The two balances were interlinked to counteract the rolling of the vessel and were controlled by helical springs operating in tension. It was the first timepiece with a balance to have temperature compensation. The effect of temperature change on the timekeeping of a balance is more pronounced than it is for a pendulum, as two effects are involved: the change in the size of the balance; and the change in the elasticity of the balance spring. Harrison compensated for both effects by using a gridiron arrangement to alter the tension in the springs. This timekeeper performed creditably when it was tested on a voyage to Lisbon, and the Board of Longitude agreed to finance improved models. Harrison's second timekeeper dispensed with the use of wood and had the added refinement of a remontoire, but even before it was tested he had embarked on a third machine. The balance of this machine was controlled by a spiral spring whose effective length was altered by a bimetallic strip to compensate for changes in temperature. In 1753 Harrison commissioned a London watchmaker, John Jefferys, to make a watch for his own personal use, with a similar form of temperature compensation and a modified verge escapement that was intended to compensate for the lack of isochronism of the balance spring. The time-keeping of this watch was surprisingly good and Harrison proceeded to build a larger and more sophisticated version, with a remontoire. This timekeeper was completed in 1759 and its performance was so remarkable that Harrison decided to enter it for the longitude prize in place of his third machine. It was tested on two voyages to the West Indies and on both occasions it met the requirements of the Act, but the Board of Longitude withheld half the prize money until they had proof that the timekeeper could be duplicated. Copies were made by Harrison and by Larcum Kendall, but the Board still continued to prevaricate and Harrison received the full amount of the prize in 1773 only after George III had intervened on his behalf.

Although Harrison had shown that it was possible to construct a timepiece of sufficient accuracy to determine longitude at sea, his solution was too complex and costly to be produced in quantity. It had, for example, taken Larcum Kendall two years to produce his copy of Harrison's fourth timekeeper, but Harrison had overcome the psychological barrier and opened the door for others to produce chronometers in quantity at an affordable price. This was achieved before the end of the century by Arnold and Earnshaw, but they used an entirely different design that owed more to Le Roy than it did to Harrison and which only retained Harrison's maintaining power.

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See also: Burgi, Jost; Huygens, Christiaan

SUBJECT AREA: Automotive engineering, Mechanical, pneumatic and hydraulic engineering

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Carl Edvard Johansson was first apprenticed to a shoemaker, but he soon abandoned that career. In 1882 he went to America to join his brother Arvid working at a sawmill in the summer; in winter the brothers obtained further general education at the Gustavus Adolphus College at St Peter, Minnesota. They returned to Sweden in November 1884 and in the following year Carl obtained employment with a small engineering firm which rented a workshop in the government small-arms factory at Eskilstuna. In his spare time he attended the Eskilstuna Technical College and in 1888 he was accepted as an apprentice armourer inspector. After completion of his apprenticeship he was appointed an armourer inspector, and it was in his work of inspection that he realized that the large number of gauges then required could be reduced if several accurate gauges could be used in combination. This was in 1896, and the first set of gauges was made for use in the rifle factory. With these, any dimension between 1 mm and 201 mm could be made up to the nearest 0.01 mm, the gauges having flat polished surfaces that would adhere together by "wringing". Johansson obtained patents for the system from 1901, but it was not until c.1907 that the sets of gauges were marketed generally. Gauges were made in inch units for Britain and America—slightly different as the standards were not then identical. Johansson formed his own company to manufacture the gauges in 1910, but he did not give up his post in the rifle factory until 1914. By the 1920s Johansson gauges were established as the engineering dimensional standards for the whole world; the company also made other precision measuring instruments such as micrometers and extensometers. A new company, C.E.Johansson Inc., was set up in America for manufacture and sales, and the gauges were extensively used in the American automobile industry. Henry Ford took a special interest and Johansson spent several years in a post with the Ford Motor Company in Detroit, Michigan, until he returned to Sweden in 1936.

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SUBJECT AREA: Textiles

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John Kay was the youngest of five sons of a yeoman farmer of Walmersley, near Bury, Lancashire, who died before his birth. John was apprenticed to a reedmaker, and just before he was 21 he married a daughter of John Hall of Bury and carried on his trade in that town until 1733. It is possible that his first patent, taken out in 1730, was connected with this business because it was for an engine that made mohair thread for tailors and twisted and dressed thread; such thread could have been used to bind up the reeds used in looms. He also improved the reeds by making them from metal instead of cane strips so they lasted much longer and could be made to be much finer. His next patent in 1733, was a double one. One part of it was for a batting machine to remove dust from wool by beating it with sticks, but the patent is better known for its description of the flying shuttle. Kay placed boxes to receive the shuttle at either end of the reed or sley. Across the open top of these boxes was a metal rod along which a picking peg could slide and drive the shuttle out across the loom. The pegs at each end were connected by strings to a stick that was held in the right hand of the weaver and which jerked the shuttle out of the box. The shuttle had wheels to make it "fly" across the warp more easily, and ran on a shuttle race to support and guide it. Not only was weaving speeded up, but the weaver could produce broader cloth without any aid from a second person. This invention was later adapted for the power loom. Kay moved to Colchester and entered into partnership with a baymaker named Solomon Smith and a year later was joined by William Carter of Ballingdon, Essex. His shuttle was received with considerable hostility in both Lancashire and Essex, but it was probably more his charge of 15 shillings a year for its use that roused the antagonism. From 1737 he was much involved with lawsuits to try and protect his patent, particularly the part that specified the method of winding the thread onto a fixed bobbin in the shuttle. In 1738 Kay patented a windmill for working pumps and an improved chain pump, but neither of these seems to have been successful. In 1745, with Joseph Stell of Keighley, he patented a narrow fabric loom that could be worked by power; this type may have been employed by Gartside in Manchester soon afterwards. It was probably through failure to protect his patent rights that Kay moved to France, where he arrived penniless in 1747. He went to the Dutch firm of Daniel Scalongne, woollen manufacturers, in Abbeville. The company helped him to apply for a French patent for his shuttle, but Kay wanted the exorbitant sum of £10,000. There was much discussion and eventually Kay set up a workshop in Paris, where he received a pension of 2,500 livres. However, he was to face the same problems as in England with weavers copying his shuttle without permission. In 1754 he produced two machines for making card clothing: one pierced holes in the leather, while the other cut and sharpened the wires. These were later improved by his son, Robert Kay. Kay returned to England briefly, but was back in France in 1758. He was involved with machines to card both cotton and wool and tried again to obtain support from the French Government. He was still involved with developing textile machines in 1779, when he was 75, but he must have died soon afterwards. As an inventor Kay was a genius of the first rank, but he was vain, obstinate and suspicious and was destitute of business qualities.

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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: Textiles

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John Lombe's father, Henry Lombe, was a worsted weaver who married twice. John was the second son of the second marriage and was still a baby when his father died in 1695. John, a native of the Eastern Counties, was apprenticed to a trade and employed by Thomas Cotchett in the erection of Cotchett's silk mill at Derby, which soon failed however. Lombe went to Italy, or was sent there by his elder half-brother, Thomas, to discover the secrets of their throwing machinery while employed in a silk mill in Piedmont. He returned to England in 1716 or 1717, bringing with him two expert Italian workmen.

Thomas Lombe was a prosperous London merchant who financed the construction of a new water-powered silk mill at Derby which is said to have cost over £30,000. John arranged with the town Corporation for the lease of the island in the River Derwent, where Cotchett had erected his mill. During the four years of its construction, John first set up the throwing machines in other parts of the town. The machines were driven manually there, and their product helped to defray the costs of the mill. The silk-throwing machine was very complex. The water wheel powered a horizontal shaft that was under the floor and on which were placed gearwheels to drive vertical shafts upwards through the different floors. The throwing machines were circular, with the vertical shafts running through the middle. The doubled silk threads had previously been wound on bobbins which were placed on spindles with wire flyers at intervals around the outer circumference of the machine. The bobbins were free to rotate on the spindles while the spindles and flyers were driven by the periphery of a horizontal wheel fixed to the vertical shaft. Another horizontal wheel set a little above the first turned the starwheels, to which were attached reels for winding the silk off the bobbins below. Three or four sets of these spindles and reels were placed above each other on the same driving shaft. The machine was very complicated for the time and must have been expensive to build and maintain.

John lived just long enough to see the mill in operation, for he died in 1722 after a painful illness said to have been the result of poison administered by an Italian woman in revenge for his having stolen the invention and for the injury he was causing the Italian trade. The funeral was said to have been the most superb ever known in Derby.

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SUBJECT AREA: Aerospace, Weapons and armour

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Maxim was born the son of a pioneer farmer who later became a wood turner. Young Maxim was first apprenticed to a carriage maker and then embarked on a succession of jobs before joining his uncle in his engineering firm in Massachusetts in 1864. As a young man he gained a reputation as a boxer, but it was his uncle who first identified and encouraged Hiram's latent talent for invention.

It was not, however, until 1878, when Maxim joined the first electric-light company to be established in the USA, as its Chief Engineer, that he began to make a name for himself. He developed an improved light filament and his electric pressure regulator not only won a prize at the first International Electrical Exhibition, held in Paris in 1881, but also resulted in his being made a Chevalier de la Légion d'honneur. While in Europe he was advised that weapons development was a more lucrative field than electricity; consequently, he moved to England and established a small laboratory at Hatton Garden, London. He began by investigating improvements to the Gatling gun in order to produce a weapon with a faster rate of fire and which was more accurate. In 1883, by adapting a Winchester carbine, he successfully produced a semi-automatic weapon, which used the recoil to cock the gun automatically after firing. The following year he took this concept a stage further and produced a fully automatic belt-fed weapon. The recoil drove barrel and breechblock to the vent. The barrel then halted, while the breechblock, now unlocked from the former, continued rearwards, extracting the spent case and recocking the firing mechanism. The return spring, which it had been compressing, then drove the breechblock forward again, chambering the next round, which had been fed from the belt, as it did so. Keeping the trigger pressed enabled the gun to continue firing until the belt was expended. The Maxim gun, as it became known, was adopted by almost every army within the decade, and was to remain in service for nearly fifty years. Maxim himself joined forces with the large British armaments firm of Vickers, and the Vickers machine gun, which served the British Army during two world wars, was merely a refined version of the Maxim gun.

Maxim's interests continued to occupy several fields of technology, including flight. In 1891 he took out a patent for a steam-powered aeroplane fitted with a pendulous gyroscopic stabilizer which would maintain the pitch of the aeroplane at any desired inclination (basically, a simple autopilot). Maxim decided to test the relationship between power, thrust and lift before moving on to stability and control. He designed a lightweight steam-engine which developed 180 hp (135 kW) and drove a propeller measuring 17 ft 10 in. (5.44 m) in diameter. He fitted two of these engines into his huge flying machine testrig, which needed a wing span of 104 ft (31.7 m) to generate enough lift to overcome a total weight of 4 tons. The machine was not designed for free flight, but ran on one set of rails with a second set to prevent it rising more than about 2 ft (61 cm). At Baldwyn's Park in Kent on 31 July 1894 the huge machine, carrying Maxim and his crew, reached a speed of 42 mph (67.6 km/h) and lifted off its rails. Unfortunately, one of the restraining axles broke and the machine was extensively damaged. Although it was subsequently repaired and further trials carried out, these experiments were very expensive. Maxim eventually abandoned the flying machine and did not develop his idea for a stabilizer, turning instead to other projects. At the age of almost 70 he returned to the problems of flight and designed a biplane with a petrol engine: it was built in 1910 but never left the ground.

In all, Maxim registered 122 US and 149 British patents on objects ranging from mousetraps to automatic spindles. Included among them was a 1901 patent for a foot-operated suction cleaner. In 1900 he became a British subject and he was knighted the following year. He remained a larger-than-life figure, both physically and in character, until the end of his life.

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See also: Pilcher, Percy Sinclair

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SUBJECT AREA: Electricity, Ports and shipping

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The youngest son of the Earl of Rosse, he came from a family well known in scientific circles, the six boys growing up in an intellectual atmosphere at Birr Castle, the ancestral home in Ireland, where a forge and large workshop were available to them. Charles, like his brothers, did not go to school but was educated by private tutors of the character of Sir Robert Ball, this type of education being interspersed with overseas holiday trips to France, Holland, Belgium and Spain in the family yacht. In 1871, at the age of 17, he went to Trinity College, Dublin, and after two years he went on to St John's College, Cambridge. This was before the Engineering School had opened, and Parsons studied mechanics and mathematics.

In 1877 he was apprenticed to W.G.Armstrong \& Co. of Elswick, where he stayed for four years, developing an epicycloidal engine that he had designed while at Cambridge. He then moved to Kitson \& Co. of Leeds, where he went half shares in a small experimental shop working on rocket propulsion for torpedoes.

In 1887 he married Katherine Bethell, who contracted rheumatic fever from early-morning outdoor vigils with her husband to watch his torpedo experiments while on their honeymoon! He then moved to a partnership in Clarke, Chapman \& Co. at Gateshead. There he joined the electrical department, initially working on the development of a small, steam-driven marine lighting set. This involved the development of either a low-speed dynamo, for direct coupling to a reciprocating engine, or a high-speed engine, and it was this requirement that started Parsons on the track of the steam turbine. This entailed many problems such as the running of shafts at speeds of up to 40,000 rpm and the design of a DC generator for 18,000 rpm. He took out patents for both the turbine and the generator on 23 April 1884. In 1888 he dissolved his partnership with Clarke, Chapman \& Co. to set up his own firm in Newcastle, leaving his patents with the company's owners. This denied him the use of the axial-flow turbine, so Parsons then designed a radial-flow layout; he later bought back his patents from Clarke, Chapman \& Co. His original patent had included the use of the steam turbine as a means of marine propulsion, and Parsons now set about realizing this possibility. He experimented with 2 ft (61 cm) and 6 ft (183 cm) long models, towed with a fishing line or, later, driven by a twisted rubber cord, through a single-reduction set of spiral gearing.

The first trials of the Turbinia took place in 1894 but were disappointing due to cavitation, a little-understood phenomenon at the time. He used an axial-flow turbine of 2,000 shp running at 2,000 rpm. His work resulted in a far greater understanding of the phenomenon of cavitation than had hitherto existed. Land turbines of up to 350 kW (470 hp) had meanwhile been built. Experiments with the Turbinia culminated in a demonstration which took place at the great Naval Review of 1897 at Spithead, held to celebrate Queen Victoria's Diamond Jubilee. Here, the little Turbinia darted in and out of the lines of heavy warships and destroyers, attaining the unheard of speed of 34.5 knots. The following year the Admiralty placed their first order for a turbine-driven ship, and passenger vessels started operation soon after, the first in 1901. By 1906 the Admiralty had moved over to use turbines exclusively. These early turbines had almost all been direct-coupled to the ship's propeller shaft. For optimum performance of both turbine and propeller, Parsons realized that some form of reduction gearing was necessary, which would have to be extremely accurate because of the speeds involved. Parsons's Creep Mechanism of 1912 ensured that any errors in the master wheel would be distributed evenly around the wheel being cut.

Parsons was also involved in optical work and had a controlling interest in the firm of Ross Ltd of London and, later, in Sir Howard Grubb \& Sons. He he was an enlightened employer, originating share schemes and other benefits for his employees.

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SUBJECT AREA: Electricity, Electronics and information technology, Photography, film and optics

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Paul was educated at the City of London School and Finsbury Technical College. He worked first for a short time in the Bell Telephone Works in Antwerp, Belgium, and then in the electrical instrument shop of Elliott Brothers in the Strand until 1891, when he opened an instrument-making business at 44 Hatton Garden, London. He specialized in the design and manufacture of electrical instruments, including the Ayrton Mather galvanometer. In 1902, with a purpose-built factory, he began large batch production of his instruments. He also opened a factory in New York, where uncalibrated instruments from England were calibrated for American customers. In 1903 Paul introduced the Unipivot galvanometer, in which the coil was supported at the centre of gravity of the moving system on a single pivot. The pivotal friction was less than in a conventional instrument and could be used without accurate levelling, the sensitivity being far beyond that of any pivoted galvanometer then in existence.

In 1894 Paul was asked by two entrepreneurs to make copies of Edison's kinetoscope, the pioneering peep-show moving-picture viewer, which had just arrived in London. Discovering that Edison had omitted to patent the machine in England, and observing that there was considerable demand for the machine from show-people, he began production, making six before the end of the year. Altogether, he made about sixty-six units, some of which were exported. Although Edison's machine was not patented, his films were certainly copyrighted, so Paul now needed a cinematographic camera to make new subjects for his customers. Early in 1895 he came into contact with Birt Acres, who was also working on the design of a movie camera. Acres's design was somewhat impractical, but Paul constructed a working model with which Acres filmed the Oxford and Cambridge Boat Race on 30 March, and the Derby at Epsom on 29 May. Paul was unhappy with the inefficient design, and developed a new intermittent mechanism based on the principle of the Maltese cross. Despite having signed a ten-year agreement with Paul, Acres split with him on 12 July 1895, after having unilaterally patented their original camera design on 27 May. By the early weeks of 1896, Paul had developed a projector mechanism that also used the Maltese cross and which he demonstrated at the Finsbury Technical College on 20 February 1896. His Theatrograph was intended for sale, and was shown in a number of venues in London during March, notably at the Alhambra Theatre in Leicester Square. There the renamed Animatographe was used to show, among other subjects, the Derby of 1896, which was won by the Prince of Wales's horse "Persimmon" and the film of which was shown the next day to enthusiastic crowds. The production of films turned out to be quite profitable: in the first year of the business, from March 1896, Paul made a net profit of £12,838 on a capital outlay of about £1,000. By the end of the year there were at least five shows running in London that were using Paul's projectors and screening films made by him or his staff.

Paul played a major part in establishing the film business in England through his readiness to sell apparatus at a time when most of his rivals reserved their equipment for sole exploitation. He went on to become a leading producer of films, specializing in trick effects, many of which he pioneered. He was affectionately known in the trade as "Daddy Paul", truly considered to be the "father" of the British film industry. He continued to appreciate fully the possibilities of cinematography for scientific work, and in collaboration with Professor Silvanus P.Thompson films were made to illustrate various phenomena to students.

Paul ended his involvement with film making in 1910 to concentrate on his instrument business; on his retirement in 1920, this was amalgamated with the Cambridge Instrument Company. In his will he left shares valued at over £100,000 to form the R.W.Paul Instrument Fund, to be administered by the Institution of Electrical Engineers, of which he had been a member since 1887. The fund was to provide instruments of an unusual nature to assist physical research.

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SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

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Jesse Ramsden was the son of an innkeeper but received a good general education: after attending the free school at Halifax, he was sent at the age of 12 to his uncle for further study, particularly in mathematics. At the age of 16 he was apprenticed to a cloth-worker in Halifax and on completion of the apprenticeship in 1755 he moved to London to work as a clerk in a cloth warehouse. In 1758 he became an apprentice in the workshop of a London mathematical instrument-maker named Burton. He quickly gained the skill, particularly in engraving, and by 1762 he was able to set up on his own account. He married in 1765 or 1766 the youngest daughter of the optician John Dollond FRS (1706– 61) and received a share of Dollond's patent for making achromatic lenses.

Ramsden's experience and reputation increased rapidly and he was generally regarded as the leading instrument-maker of his time. He opened a shop in the Haymarket and transferred to Piccadilly in 1775. His staff increased to about sixty workers and apprentices, and by 1789 he had constructed nearly 1,000 sextants as well as theodolites, micrometers, balances, barometers, quadrants and other instruments.

One of Ramsden's most important contributions to precision measurement was his development of machines for obtaining accurate division of angular and linear scales. For this work he received a premium from the Commissioners of the Board of Longitude, who published his descriptions of the machines. For the trigonometrical survey of Great Britain, initiated by General William Roy FRS (1726–90) and continued by the Board of Ordnance, Ramsden supplied a 3 ft (91 cm) theodolite and steel measuring chains, and was also engaged to check the glass tubes used to measure the fundamental base line.

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SUBJECT AREA: Metallurgy

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His family emigrated to Australia when he was 5 years old. He was educated at Wesley College, Melbourne, and attended Queen's College, University of Melbourne, graduating in physics and engineering in 1897. As an 1851 Exhibitioner he then spent three years at St John's College, Cambridge, under Sir Alfred Ewing, where he studied the microstructure of deformed metal crystals and abandoned his original intention of becoming a civil engineer. Rosenhain was the first to observe the slip-bands in metal crystals, and in the Bakerian Lecture delivered jointly by Ewing and Rosenhain to the Royal Society in 1899 it was shown that metals deformed plastically by a mechanism involving shear slip along individual crystal planes. From this conception modern ideas on the plasticity and recrystallization of metals rapidly developed. On leaving Cambridge, Rosenhain joined the Birmingham firm of Chance Brothers, where he worked for six years on optical glass and lighthouse-lens systems. A book, Glass Manufacture, written in 1908, derives from this period, during which he continued his metallurgical researches in the evenings in his home laboratory and published several papers on his work.

In 1906 Rosenhain was appointed Head of the Metallurgical Department of the National Physical Laboratory (NPL), and in 1908 he became the first Superintendent of the new Department of Metallurgy and Metallurgical Chemistry. Many of the techniques he introduced at Teddington were described in his Introduction to Physical Metallurgy, published in 1914. At the outbreak of the First World War, Rosenhain was asked to undertake work in his department on the manufacture of optical glass. This soon made it possible to manufacture optical glass of high quality on an industrial scale in Britain. Much valuable work on refractory materials stemmed from this venture. Rosenhain's early years at the NPL were, however, inseparably linked with his work on light alloys, which between 1912 and the end of the war involved virtually all of the metallurgical staff of the laboratory. The most important end product was the well-known "Y" Alloy (4% copper, 2% nickel and 1.5% magnesium) extensively used for the pistons and cylinder heads of aircraft engines. It was the prototype of the RR series of alloys jointly developed by Rolls Royce and High Duty Alloys. An improved zinc-based die-casting alloy devised by Rosenhain was also used during the war on a large scale for the production of shell fuses.

After the First World War, much attention was devoted to beryllium, which because of its strength, lightness, and stiffness would, it was hoped, become the airframe material of the future. It remained, however, too brittle for practical use. Other investigations dealt with impurities in copper, gases in aluminium alloys, dental alloys, and the constitution of alloys. During this period, Rosenhain's laboratory became internationally known as a centre of excellence for the determination of accurate equilibrium diagrams.

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SUBJECT AREA: Recording

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He was the descendant of a Scottish family who emigrated to France in 1688. He trained as a printer and later became a proof corrector in printing houses catering predominantly for scientific publishers. He became interested in shorthand systems and eventually turned his interest to making a permanent record of sounds in air. At the time it was already known (Young, Duhamel, Wertheim) to record vibrations of bodies. He made a theoretical study and deposited under sealed wrapper a note in the Académie des Sciences on 26 January 1857. He approached the scientific instrument maker Froment and was able to pay for the manufacture of one instrument due to support from the Société d'Encouragement à l'Industrie Nationale. This funding body obtained a positive report from the physicist Lissajous on 6 January 1858. A new model phonautograph was constructed in collaboration with the leading scientific instrument maker in Paris at the time, Rudolph Koenig, and a contract was signed in 1859. The instrument was a success, and Koenig published a collection of traces in 1864.

Although the membrane was parallel to the rotating surface, a primitive lever system generated lateral movements of a bristle which scratched curves in a thin layer of lampblack on the rotating surface. The curves were not necessarily representative of the vibrations in the air. Scott did not imagine the need for reproducing a recorded sound; rather, his intention was to obtain a trace that would lend itself to mathematical analysis and visual recognition of sounds. Obviously the latter did not require the same degree of linearity as the former. When Scott learned that similar apparatus had been built independently in the USA, he requested that his sealed wrapper be opened on 15 July 1861 in order to prove his scientific priority. The contract with Koenig left Scott without influence over his instrument, and eventually he became convinced that everyone else, including Edison in the end, had stolen his invention. Towards the end of his life he became interested mainly in the history of printing, and he was involved in the publishing of a series of books about books.

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SUBJECT AREA: Civil engineering, Mechanical, pneumatic and hydraulic engineering, Steam and internal combustion engines

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As a boy, Smeaton showed mechanical ability, making for himself a number of tools and models. This practical skill was backed by a sound education, probably at Leeds Grammar School. At the age of 16 he entered his father's office; he seemed set to follow his father's profession in the law. In 1742 he went to London to continue his legal studies, but he preferred instead, with his father's reluctant permission, to set up as a scientific instrument maker and dealer and opened a shop of his own in 1748. About this time he began attending meetings of the Royal Society and presented several papers on instruments and mechanical subjects, being elected a Fellow in 1753. His interests were turning towards engineering but were informed by scientific principles grounded in careful and accurate observation.

In 1755 the second Eddystone lighthouse, on a reef some 14 miles (23 km) off the English coast at Plymouth, was destroyed by fire. The President of the Royal Society was consulted as to a suitable engineer to undertake the task of constructing a new one, and he unhesitatingly suggested Smeaton. Work began in 1756 and was completed in three years to produce the first great wave-swept stone lighthouse. It was constructed of Portland stone blocks, shaped and pegged both together and to the base rock, and bonded by hydraulic cement, scientifically developed by Smeaton. It withstood the storms of the English Channel for over a century, but by 1876 erosion of the rock had weakened the structure and a replacement had to be built. The upper portion of Smeaton's lighthouse was re-erected on a suitable base on Plymouth Hoe, leaving the original base portion on the reef as a memorial to the engineer.

The Eddystone lighthouse made Smeaton's reputation and from then on he was constantly in demand as a consultant in all kinds of engineering projects. He carried out a number himself, notably the 38 mile (61 km) long Forth and Clyde canal with thirty-nine locks, begun in 1768 but for financial reasons not completed until 1790. In 1774 he took charge of the Ramsgate Harbour works.

On the mechanical side, Smeaton undertook a systematic study of water-and windmills, to determine the design and construction to achieve the greatest power output. This work issued forth as the paper "An experimental enquiry concerning the natural powers of water and wind to turn mills" and exerted a considerable influence on mill design during the early part of the Industrial Revolution. Between 1753 and 1790 Smeaton constructed no fewer than forty-four mills.

Meanwhile, in 1756 he had returned to Austhorpe, which continued to be his home base for the rest of his life. In 1767, as a result of the disappointing performance of an engine he had been involved with at New River Head, Islington, London, Smeaton began his important study of the steam-engine. Smeaton was the first to apply scientific principles to the steam-engine and achieved the most notable improvements in its efficiency since its invention by Newcomen, until its radical overhaul by James Watt. To compare the performance of engines quantitatively, he introduced the concept of "duty", i.e. the weight of water that could be raised 1 ft (30 cm) while burning one bushel (84 lb or 38 kg) of coal. The first engine to embody his improvements was erected at Long Benton colliery in Northumberland in 1772, with a duty of 9.45 million pounds, compared to the best figure obtained previously of 7.44 million pounds. One source of heat loss he attributed to inaccurate boring of the cylinder, which he was able to improve through his close association with Carron Ironworks near Falkirk, Scotland.

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SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

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He was educated by his father, Claude Vernier, and from an early age studied all kinds of instruments, both in practice and in theory. The Spanish government employed him on several commissions, before he was elected commandant of the Château d'Ornans and later Director-General of Finances and Counsellor for the county of Bourgogne. In 1631 he wrote La Construction, l'usage et les propriétés du quadrant nouveau de mathématiques ("The Construction, Uses and Properties of a New Mathematical Quadrant"), which contained tables of trigonometric sines and a method of calculating the angles of a triangle from the lengths of its sides, as well as a description of his new measuring instrument which became known as the vernier caliper.

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