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

Irish Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit ...

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...

who from 1802 was blind. He is known as the

inventor An invention is a unique or novel device, method, composition, idea or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...

of the

screw-pile lighthouse A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Construction ...

. Born in

Dublin Dublin (; , or ) is the capital and largest city of Republic of Ireland, Ireland. On a bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, bordered on the south by the Dublin Mountains, a part of th ...

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

Belfast Academy The Belfast Royal Academy (commonly shortened to ) 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 ...

– where he excelled in

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

. Originally working in brickmaking in

Belfast Belfast ( , ; from ga, Béal Feirste , meaning 'mouth of the sand-bank ford') is the capital and largest city of Northern Ireland, standing on the banks of the River Lagan on the east coast. It is the 12th-largest city in the United Kingdo ...

, 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 lenses and to serve as a beacon for navigational aid, for maritime pilots at sea or on inland waterways. Lighthouses mar ...

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 largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...

breakwater to

Bombay Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second- ...

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 The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in ...

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 salini ...

(the first light application, in 1838), at Fleetwood Lancashire (UK)

Morecambe Bay Morecambe Bay is a large estuary in northwest England, just to the south of the Lake District National Park. It is the largest expanse of intertidal mudflats and sand in the United Kingdom, covering a total area of . In 1974, the second larges ...

(the first Ever Beacon Lit ) completed, in 1839), and at

Belfast Lough Belfast Lough is a large, intertidal 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 th ...

where his lighthouse was finished in July 1844. Hopper barge apparatus 2

In 1848 he was elected member of the

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

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 following year for a paper on his invention. 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, Ireland. With a population of around 13,000 inhabitants, Cobh is on the south side of Great Island in Cork Harbour and home to Ireland's ...

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 (Vadoda ...

and a broad system of Indian telegraphs. He became friendly with

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

John Thomas Romney Robinson John Thomas Romney Robinson FRS FRSE (23 April 1792 – 28 February 1882), usually referred to as Thomas Romney Robinson, was a 19th-century Irish astronomer and physicist. He was the longtime director of the Armagh Astronomical Observatory, ...

, 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, structure, space, models, and change. History On ...

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 Ire ...

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

References

1780 births 1868 deaths People from County Dublin Irish engineers Irish inventors Lighthouse builders People educated at the Belfast Royal Academy Blind people from Ireland {{Ireland-engineer-stub