Alexander Mitchell (13 April 1780 – 25 June 1868) was an Irish

engineer Engineers, as practitioners of engineering, are professionals who Invention, invent, design, build, maintain and test machines, complex systems, structures, gadgets and materials. They aim to fulfill functional objectives and requirements while ...

who from 1802 was blind. He is known as the inventor of the screw-pile lighthouse.

Early life

Born in

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

, his family moved to Belfast while he was a child, and he received his formal education at

Belfast Royal Academy The Belfast Royal Academy (also known as ) is the oldest school in the city of Belfast, Northern Ireland. It is a co-educational, non-denominational voluntary grammar school in north Belfast. The Academy is one of 8 schools in Northern Ireland ...

, where he excelled in

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

Career

Originally working in brickmaking in

Belfast Belfast (, , , ; from ) is the capital city and principal port of Northern Ireland, standing on the banks of the River Lagan and connected to the open sea through Belfast Lough and the North Channel (Great Britain and Ireland), North Channel ...

, he invented machines used in that trade, before patenting the screw-pile in 1833, for which he would later gain some fame. The screw-pile was used for the erection of

lighthouse A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lens (optics), lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Ligh ...

s and other structures on mudbanks and shifting sands, including bridges and piers. Mitchell's designs and methods were employed all over the world from

Portland Portland most commonly refers to: *Portland, Oregon, the most populous city in the U.S. state of Oregon *Portland, Maine, the most populous city in the U.S. state of Maine *Isle of Portland, a tied island in the English Channel Portland may also r ...

breakwater to

Bombay Mumbai ( ; ), also known as Bombay ( ; its official name until 1995), is the capital city of the Indian States and union territories of India, state of Maharashtra. Mumbai is the financial centre, financial capital and the list of cities i ...

bridges. Initially it was used for the construction of lighthouses on

Maplin Sands The Maplin Sands are mudflats on the northern bank of the Thames estuary, off Foulness Island, near Southend-on-Sea in Essex, England, though they actually lie within the neighbouring borough of Rochford. They form a part of the Essex Estuaries S ...

in the

Thames Estuary The Thames Estuary is where the River Thames meets the waters of the North Sea, in the south-east of Great Britain. Limits An estuary can be defined according to different criteria (e.g. tidal, geographical, navigational or in terms of salinit ...

(the first light application, in 1838), the Wyre Light at

Fleetwood Fleetwood is a coastal town in the Borough of Wyre in Lancashire, England, at the northwest corner of the Fylde. It had a population of 25,939 at the 2011 United Kingdom census, 2011 census. Fleetwood acquired its modern character in the 1830 ...

in Lancashire (the first such beacon lit) completed, in 1839), and at

Belfast Lough Belfast Lough () is a large sea inlet on the east coast of Northern Ireland. At its head is the city and port of Belfast, which sits at the mouth of the River Lagan. The lough opens into the North Channel and connects Belfast to the Irish ...

where his lighthouse was finished in July 1844. In May 1851 he moved to

Cobh Cobh ( ,), known from 1849 until 1920 as Queenstown, is a seaport town on the south coast of County Cork, Republic of Ireland, Ireland. With a population of 14,148 inhabitants at the 2022 census of Ireland, 2022 census, Cobh is on the south si ...

to lay the foundation for a lighthouse on the Spit Bank; the success of these undertakings led to the use of his invention on the breakwater at

, the viaduct and bridges on the

Bombay, Baroda and Central India Railway The Bombay, Baroda and Central India Railway (reporting mark BB&CI) was a company incorporated in 1855 to undertake the task of constructing railway lines between Bombay to the erstwhile Baroda State, that became the present-day Baroda (Vadod ...

and a broad system of Indian telegraphs. While in Cork, Mitchell became friendly with

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

John Thomas Romney Robinson, and

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

George Boole George Boole ( ; 2 November 1815 – 8 December 1864) was a largely self-taught English mathematician, philosopher and logician, most of whose short career was spent as the first professor of mathematics at Queen's College, Cork in Ireland. H ...

Awards and honours

In 1848, he was elected a member of the

Institution of Civil Engineers The Institution of Civil Engineers (ICE) is an independent professional association for civil engineers and a Charitable organization, charitable body in the United Kingdom. Based in London, ICE has over 92,000 members, of whom three-quarters ar ...

and received the

Telford Medal The Telford Medal is a prize awarded by the British Institution of Civil Engineers (ICE) for a paper or series of papers. It was introduced in 1835 following a bequest made by Thomas Telford, the ICE's first president. It can be awarded in gold ...

the same year for a paper on his invention.

Death

Mitchell died at Glen Devis near Belfast on 25 June 1868. His wife and daughter had predeceased him.

References

External links

Mitchell, Alexander - Dictionary of Irish Biography - 2009
1780 births 1868 deaths Engineers from County Dublin Irish engineers Irish inventors Lighthouse builders People educated at the Belfast Royal Academy Irish blind people Scientists with disabilities Engineers from Belfast {{Ireland-engineer-stub