Hydraulics Heroes
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
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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. This inspired him to design a lock himself – one that was resistant to picking or tampering.
Bramah was awarded a patent for his lock in 1784 and a second in 1798. The design proved resistant to tampering: from 1790, it was displayed in the window of Bramah’s London shop with a 200-guinea challenge to open it – a challenge which stood for 67 years until an American mechanic spent 51 hours opening it during the Great Exhibition of 1851.
The precise construction of these locks and the growing demand for them led Bramah to lay the foundation stones of the machine tools industry, working with young blacksmith Henry Maudslay.
Bramah’s patents at this time included a hydrostatical machine and boiler, a beer pump, an improvement to the rotary engine, a fire engine and a rotary pump.
In 1795, he filed his most important patent: for “obtaining and applying motive power” and describing a hydraulic press with two cylinders and pistons of differing cross-sectional areas.
The basis of this invention was Pascal’s Law; that the pressure through a closed system is constant.
If a force was exerted on the smaller piston, this would translate to a larger force on the larger piston and the different would be proportional to the difference in cross-sectional area.
His invention is still known today as the Bramah Press.
Hydraulics Online e-book: Hydraulics Heroes P.10 www.hydraulicsonline.com Further inventions followed: for a planing machine, a paper-making machine, a machine for printing bank notes with sequential serial numbers and the first extrusion process for making lead pipes. His planing machine was supplied to the Royal Carriage department at what would later become the Woolwich Arsenal.
Bramah’s insistence on quality control led him to mentor Arthur Woolf, a Cornish steam engineer, to machine engines to a close tolerance – helping Woolf to vastly increase their output and become a leader in his field.
In his own workshops, Bramah deployed his own hydraulic power for sawing stone and timber. One of his last inventions was a hydrostatic press for uprooting trees. After a public demonstration in Hyde Park in 1813, in 1814 the hydrostatic press was put to work in Holt Forest in Hampshire. Bramah was supervising the work – during which 300 trees were uprooted in short order – when he caught a severe cold which worsened to pneumonia.
He died in his house in Pimlico on December 9, 1814 and is buried in Paddington churchyard. He did not live to bring to fruition his new ideas for building bridges and canal locks.
Most important contribution to hydraulics: the Bramah press.
Hydraulics Online e-book: Hydraulics Heroes P.11 www.hydraulicsonline.com Jean Léonard Marie Poiseuille
Jean Léonard Marie Poiseuille (1799 – 1869) was a French physicist and physiologist who is best known for his work on the non-turbulent flow of liquids through narrow pipes of uniform section, as in the flow of blood through capillaries and veins.
Not a lot is known about Jean Léonard Marie Poiseuille’s life beyond the papers he published on a variety of science subjects. Amongst these was his dissertation Recherches sur la force du coeur aortique, written in 1828 as part of his D.Sc. degree.
In this paper he showed that blood pressure rises and falls on expiration and inhalation using a device of his own invention, the hemodynamometer. This was a u-tube mercury manometer with potassium carbonate at the connection with the artery to prevent coagulation.
His interest in the circulation of blood led him to conduct a series of experiments between 1838 and 1846 which looked at fluid dynamics. His equation, published in 1846, states that the flow rate of non- turbulent liquids is determined by the viscosity of the fluid, the drop in pressure along the tube and the tube diameter.
Poiseuille was an elected member of the Paris Academy of Medicine but was never successful in his bids to win election to the Paris Academy of Science. In 1860 Jacob Eduard Hagenbach named the law after Poiseuille, but in that same year Poiseuille went to work as Inspector of School Sanitation in the Seine district. He died in 1869 in Paris.
In 1925, Whilhelm Ostwald argued that the law should be renamed the Hagen-Poiseuille law to acknowledge the work of German hydraulic engineer Gotthilf Hagen who had found the same law in 1839 but had used the wrong velocity profile in his work.
Most important contribution to hydraulics: Poiseuille’s law, now more commonly known as the Hagen- Poiseuille equation.
Hydraulics Online e-book: Hydraulics Heroes P.12 www.hydraulicsonline.com William Armstrong
William Armstrong (1810 – 1900) has a difficult legacy. While his inventiveness and industrialism would make him the inventor of the modern artillery and, as a result, the world’s first international arms dealer, his social legacy is equally compelling.
In its heyday, his works at Elswick on the north bank of the River Tyne employed more than 25,000 people, manufacturing hydraulic cranes, ships and armaments.
His father had been a grain merchant in Newcastle upon Tyne who had risen to become the town’s mayor in 1850. Armstrong was educated at the town’s Royal Grammar School and, later, at Bishop Auckland Grammar School. Here, he would visit the local engineering works, where he met his wife Margaret, daughter of the work’s owner, William Ramshaw.
Armstrong spent the next five years in London reading Law and, on returning to Newcastle in 1833, he became junior partner in the legal firm of a friend of his father’s.
Although Armstrong worked as a solicitor for eleven years, he continued to pursue his interest in engineering. In the summer of 1835, while fishing on the River Dee, he saw a waterwheel in action and realised how much of the available power was wasted.
Hydraulics Online e-book: Hydraulics Heroes P.13 www.hydraulicsonline.com Armstrong recounted, “I was lying idly about, watching an old watermill, when it occured to me what a small part of the power of the water was used in driving the wheel, and then I thought how great would be the force of even a small quantity of water if its energy were only concentrated in one column. When I returned to Newcastle, I set to work at Watson’s works, where I had been in the habit of making mechanical experiments, trying to practically realise the idea.”
From these experiments, Armstrong designed a rotary engine that was built and installed at his friend’s works, before developing a piston engine that could drive a hydraulic crane. This work would feature in an 1845 scheme to bring water to Newcastle.
Armstrong proposed that the excess water pressure in the lower part of town could power a hydraulic crane of his own design for unloading ships faster. It was such a success that four cranes were installed.
In 1846, his work as an amateur scientist was recognised in his election as a Fellow of the Royal Society.
He resigned from his legal practice, and with the financial backing of his old partner, bought the land at Elswick where he would build his factory.
Hydraulics Online e-book: Hydraulics Heroes P.14 www.hydraulicsonline.com His hydraulic cranes were soon in use on railways and docks across Scotland and England and the company diversified into bridge building – including creating the mechanisms for London’s iconic Tower Bridge and Newcastle’s Swing Bridge.
Where water pressure was not available onsite to power his cranes, Armstrong would often build water towers to supply water at pressure. When working on the Humber Estuary, where the sandy conditions prevented the construction of a water tower, Armstrong invented the hydraulic accumulator.
This weighted accumulator consisted of a cast-iron cylinder fitted with a weighted plunger. The plunger would slowly be raised, drawing in water, until the downward force of the weight was sufficient to force the water below it into pipes at great pressure.
In 1854, after reading about the difficulties of the British Army in manoeuvring heavy field guns during the Crimean War, Armstrong built a breech-loading gun – first with five-pound shells, then 18-pounders.
Following successful tests, Armstrong surrendered the patent to the British government and in 1859 was appointed “Engineer of Rifled Ordinance” and received a knighthood from Queen Victoria.
However, in 1863, the British Government reverted to muzzle-loading artillery manufactured at Woolwich. The following year, Armstrong resigned from his post with the War Office.
Hydraulics Online e-book: Hydraulics Heroes P.15 www.hydraulicsonline.com At this time, he stepped back from day-to-day operations at his company and spent time on other projects, such as the landscaping of the gardens around his house at Jesmond Dene and the building of a new house near Rothbury called Cragside (now owned by the National Trust).
Here, he planted more than 7 million trees and built five artificial lakes which would power the hydro-electricity lighting in the house. It was the first house in the world to be powered by hydro-electricity.
Even in the 1860s, Armstrong was warning about the unsustainability of fossil fuels and promoting hydro and solar power sources.
In 1871, he founded the College of Physical Science, which would later become Armstrong College in 1904 and, eventually, the University of Newcastle. He also contributed substantially to the building of the Hancock Natural History Museum in the city. He was spending more and more time at Cragside and, in 1883, Armstrong gifted Jesmond Dene to the city of Newcastle.
Meanwhile, his guest list at Cragside included the Shah of Persia, the King of Siam, the Prime Minister of China and the future King Edward VII and Queen Alexandra. He forged business links with governments around the world to sell his arms.
However, Armstrong didn’t see himself as a warmonger; he thought larger guns would act as a deterrent since “civilised” leaders would be too wise to use them.
Hydraulics Online e-book: Hydraulics Heroes P.16 www.hydraulicsonline.com In 1887, Queen Victoria made him Baron Armstrong of Cragside; the first engineer or scientist to be raised to the peerage.
He began his last great project in 1894, to restore the magnificent Bamburgh Castle on the Northumbrian Coast, which remains today in the hands of the Armstrong family.
Armstrong died on 27 December 1900, bequeathing more than £100,000 for the building of the new Royal Victoria Infirmary in Newcastle upon Tyne; the last of seven hospitals he endowed to the city.
Most important contribution to hydraulics: the invention of the hydraulic engine and the hydraulic accumulator, and the widespread deployment of major hydraulic systems, including iconic projects such as the hydraulic mechanisms in London’s Tower Bridge.
Hydraulics Online e-book: Hydraulics Heroes P.17 www.hydraulicsonline.com The wonderful world of hydraulics
The ingenuity of these five great scientists, mathmeticians and engineers still informs the basis of modern hydraulic systems.
Their work has made the hydraulic engineering we do today possible.
To discover more about the wonderful world of hydraulics, explore the other titles in this series: • The Beginner’s Guide to Hydraulics • Glossary of Hydraulics • Introduction to ATEX
Hydraulics Online e-book: Hydraulics Heroes P.18 www.hydraulicsonline.com Hydraulics Online e-book series: Sharing our knowledge of all things hydraulic
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