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Hydraulics Heroes An introduction to five influential scientists, mathematicians and engineers who paved the way for modern hydraulics: our hydraulics heroes. www.hydraulicsonline.com Hydraulics Online e-book series: Sharing our knowledge of all things hydraulic About Hydraulics Online Hydraulics Online is a leading, award-winning, ISO 9001 accredited provider of customer-centric fluid power solutions to 130 countries and 24 sectors worldwide. Highly committed employees and happy customers are the bedrock of our business. Our success is built on quality and technical know-how and the fact that we are 100% independent – we provide truly unbiased advice and the most optimal solutions for our customers. Every time. RITISH B T E R G U S A T T I Q R E U H A L Y I T Hydraulics Heroes We invite you to meet five of our hydraulics heroes: Hydraulics Online e-book series: Benedetto Castelli (c.1577 – 1642) Sharing our knowledge of all things hydraulic Blaise Pascal (1623 – 1662) Joseph Bramah (1748 – 1814) Jean Léonard Marie Poiseuille (1799 – 1869) William Armstrong (1810 – 1900) Hydraulics Online e-book: Hydraulics Heroes P. 3 www.hydraulicsonline.com Benedetto Castelli Benedetto Castelli (c.1577 – 1642) is celebrated for his work in astronomy and hydraulics. His most celebrated work is Della Misura delle Acque Correnti – On the Measurement of Running Water – which was published in 1629. In this work, Castelli established the continuity principle, which is still central to all modern hydraulics. A supporter and colleague of Galileo, Benedetto was born the eldest of seven children of a wealthy landowner. It is not known exactly when he was born, but it is thought to be 1577 or 1578. He was baptised Antonio but took the name Benedetto when he entered the Benedictine order at the monastery of Saints Faustino and Giovalta in Brescia in 1595. Castelli began studying mathematics while at Brescia. Then, when he was transferred to the monastery of Saint Giustina in Padua, he first attended the lectures of Galileo. Galileo was a friend of the abbot and met frequently with the monks. Castelli initially took the role of student, but the men later became friends who corresponded regularly about the sciences, mathematics and astronomy. In 1613, Castelli was recommended by Galileo for the post of Professor of Mathematics at the University of Pisa and was duly appointed. He lived at the Jesuiti monastery of San Girolamo as Pisa had no Benedictine monastery at the time. During this period, Castelli had to be careful about his teaching, and was forced to teach his students that the Earth is stationary – against his admiration of Galileo’s work. In 1623 Castelli visited Rome following the Papal inauguration of Pope Urban VIII and was appointed to take care of the waterways of Ferrara and Bologna. This inspired him to undertake new research on hydraulics during the remainder of his time in Pisa, visiting and corresponding regularly with Galileo to debate the topic. Hydraulics Online e-book: Hydraulics Heroes P. 4 www.hydraulicsonline.com Three years later, the Pope called Castelli to Rome to advise on the waterways of the city, where he sought explain why the River Tiber was overflowing. Castelli also tutored the Pope’s nephew in mathematics and was appointed reader of mathematics at La Sapienza university the following year. His students at this time included Evangelista Torricelli, inventor of the first barometer. A year later, Castelli’s famous book on hydraulics was published in Rome. The Incompressibility of Water was an essential prerequisite to Castelli’s mathematical formulation of the continuity law of running water – challenging the wisdom of the time. Despite unhappiness with the Inquisition’s investigation of Galileo and the scientist’s subsequent imprisonment, Castelli was persuaded to stay in Rome and was entrusted with the formal oversight of four Benedictine abbeys. He continued to work and correspond with his mentor Galileo and went on to contribute to the science of heat, metrology and magnets as well as advising on the waterways at Lake Trasimeno and the Venice Lagoon. Castelli died in 1642. His tomb can be found in the Basilica of San Paolo fuori le Mura, in the tomb of the Cassino monks. Most important contribution to hydraulics: mathematical formulation of the continuity law of running water based on the incompressibility of the liquid. Hydraulics Online e-book: Hydraulics Heroes P. 5 www.hydraulicsonline.com Blaise Pascal Blaise Pascal (1623 – 1662) is responsible for giving modern hydraulics its most fundamental principle: a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid. Despite his important contribution to modern hydraulics, it is testament to his abilities that this is not what Pascal is best remembered for. Born in 1623 in Clermont in the Auvergne region of central France, his father moved the family to Paris in 1631 following the death of Pascal’s mother. He was educated at home via an unorthodox curriculum of his father’s design which focused heavily on the classics, including learning Latin and Greek. However, Pascal was interested in mathematics and began exploring geometry on his own. Impressed by his son’s abilities, his father allowed him to read the works of Euclid and accompany him to meetings at Mersenne’s Academy in Paris where he was allowed to present some of his early theorems. Following riots which risked his father’s imprisonment in the Bastille in 1638, the youngest sister Jacqueline – a teenage prodigy who performed poetry and plays at court – intervened with Cardinal Richelieu to obtain the pardon of her father. Richelieu agreed and appointed him the royal superintendent of tax collection in the province of Normandy. So, in 1640, the family moved again – this time to Rouen. Hydraulics Online e-book: Hydraulics Heroes P. 6 www.hydraulicsonline.com Inspired to assist his father fulfil his role as tax collector of Normandy, in 1642 Pascal began work on a numerical wheel with movable dials that could help with tax computations. Although the Pascaline had several iterations and never sold widely, it is considered by some to be the first digital calculator since it operated by counting integers. Indeed, in the 1960s the Swiss computer scientist Nicklaus Werth insisted on naming his computer programming language Pascal after Pascal’s early computing machine achievements. By 1648, Pascal had begun writing his mathematical theorems in The Generation of Conic Sections but became interested in experiments in the physical sciences. Pascal tested the theories of Galileo and Evangelista Torricelli, reproducing and amplifying experiments on atmospheric pressure with the help of his brother-in-law. It was this work in hydrodynamics and hydrostatics that led Pascal to set out his famous hydraulic principle. His subsequent studies on the problem of the vacuum, the equilibrium of liquid solutions, the weight and density of air and the arithmetic triangle further cemented his reputation. Hydraulics Online e-book: Hydraulics Heroes P. 7 www.hydraulicsonline.com In the 1650s, Pascal attempted to create a perpetual motion machine that would create more energy than it used – in the process inventing what we now know as the roulette wheel. His subsequent correspondence with mathematical theorist Pierre de Fermat formed the basis of the mathematical theory of probability. Pascal’s interest in probability lies behind his most notorious theory, known as Pascal’s Wager. In it, he states that it is better for religious sceptics to embrace God as the non-believer has more to lose after death if they are wrong. This was not Pascal’s only religious text. The family had converted to Jansenism in 1646 and ten years later, between 1656 and 1657, Pascal wrote a series of open letters which defended a Sorbonne theologian who had argued for Jansenist beliefs. These anonymously-published letters subsequently became known as Les Provinciales. Pascal’s taut, precise prose, rich in irony and satire, contrasted with the bombast and rhetoric of the period and is considered by some to mark the beginning of modern French prose. His later notes, written from 1657 to the time of his death in 1662 at just 39 years old, were organised after his death into a collection called Pensées and are among Pascal’s best-known works. Most important contribution to hydraulics: Pascal’s Law. Hydraulics Online e-book: Hydraulics Heroes P. 8 www.hydraulicsonline.com Joseph Bramah Joseph Bramah (1748 – 1814) was a prolific inventor and one of two major British industrialists who contributed much to the field of hydraulics. He is best known as a locksmith and as the inventor of the hydraulic press. Bramah was born at Stainborough Lane Farm, Wentworth near Barnsley in Yorkshire, England. An injury caused him to move from farm labouring to woodworking and, after leaving school, he was apprenticed to a local carpenter. By 1773, he had finished his apprenticeship and moved to London to become a cabinetmaker in the employ of a Mr Allen who specialised in installing “water closets” – the new flush toilets designed by Alexander Cummings. Allen had improved Cumming’s original design to reduce the risk of these early toilets freezing and this invention would be the first of the patents filed by Bramah. Bramah obtained the patent in 1778 and began manufacturing water closets in a workshop in Denmark Street, St Giles. Today, his original water closets can still be seen in working order at Osborne House, Queen Victoria’s home on the Isle of Wight. Hydraulics Online e-book: Hydraulics Heroes P. 9 www.hydraulicsonline.com In 1783, Bramah joined the Society of Arts, where he attended some technical presentations on locks.

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