John Loudon McAdam
Encyclopedia
John Loudon McAdam was a Scottish
engineer
and road
-builder. He invented a new process, "macadam
isation", for building roads with a smooth hard surface that would be more durable and less muddy than soil
-based tracks.
Modern road construction still reflects McAdam's influence. Of subsequent improvements, the most significant was the introduction of tar
(originally coal tar
) to bind the road surface's stones together – "tarmac
" (for Tar Macadam) – followed later by the use of hot-laid tarred aggregate
or tar-sprayed chippings to create better road metalling
. More recently, oil
-based asphalt
laid on reinforced concrete
has become a major road surface, but its use of granite or limestone
chippings still recalls McAdam's innovation.
, Scotland
. He was the youngest of ten children and second son of the Baron of Waterhead. The family name had traditionally been McGregor, but was changed to McAdam (claiming descent from the Biblical Adam) for political reasons in James I
's reign. He moved to New York
in 1770 and, as a merchant
and prize agent during the American Revolution
, made his fortune working at his uncle's counting house
. He returned to Scotland in 1783 and purchased an estate at Sauchrie, Ayrshire
.
, England and he became general surveyor for the Bristol Corporation in 1804. He put forward his ideas in evidence to Parliamentary
enquiries in 1810, 1819 and 1823. In two treatise
s written in 1816 and 1819 (Remarks on the Present System of Road-Making and Practical Essay on the Scientific Repair and Preservation of Roads) he argued that roads needed to be raised above the surrounding ground and constructed from layered rocks and gravel in a systematic manner.
McAdam had also been appointed surveyor to the Bristol Turnpike Trust
in 1816, where he decided to remake the roads under his care with crushed stone
bound with gravel on a firm base of large stones. A camber
, making the road slightly convex, ensured rainwater rapidly drained off the road rather than penetrate and damage the road's foundations. This construction method, the greatest advance in road construction since Roman
times, became known as "macadamisation", or, more simply, "macadam
".
The macadam method spread very quickly across the world. The first macadam road in North America
, the National Road
, was completed in the 1830s and most of the main roads in Europe
were macadamized by the end of the nineteenth century.
Although McAdam was paid £
5,000 for his Bristol Turnpike Trust work and made "Surveyor-General of Metropolitan Roads" in 1820, professional jealousy cut a £5,000 grant for expenses from the Parliament of the United Kingdom
to £2,000 in 1827. His efficient road-building and management work had revealed the corruption and abuse of road toll
s by unscrupulous Turnpike Trusts, many of which were run at a deliberate loss despite high toll receipts.
, Dumfriesshire
, while returning to his home in Hoddesdon
, Hertfordshire
, from his annual summer visit to Scotland. His three sons, and in turn four grandsons, followed him into the profession and assisted with the management of turnpike trusts around the country. His second surviving son, James Nicholl McAdam, the "Colossus of Roads", was knighted for managing turnpike trusts—a knighthood, it is said, previously offered to his father but declined.
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
and road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
-builder. He invented a new process, "macadam
Macadam
Macadam is a type of road construction pioneered by the Scotsman John Loudon McAdam in around 1820. The method simplified what had been considered state-of-the-art at that point...
isation", for building roads with a smooth hard surface that would be more durable and less muddy than soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
-based tracks.
Modern road construction still reflects McAdam's influence. Of subsequent improvements, the most significant was the introduction of tar
Tar
Tar is modified pitch produced primarily from the wood and roots of pine by destructive distillation under pyrolysis. Production and trade in tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden vessels against rot. The largest...
(originally coal tar
Coal tar
Coal tar is a brown or black liquid of extremely high viscosity, which smells of naphthalene and aromatic hydrocarbons. Coal tar is among the by-products when coal iscarbonized to make coke or gasified to make coal gas...
) to bind the road surface's stones together – "tarmac
Tarmac
Tarmac is a type of road surface. Tarmac refers to a material patented by Edgar Purnell Hooley in 1901...
" (for Tar Macadam) – followed later by the use of hot-laid tarred aggregate
Aggregate (composite)
Aggregate is the component of a composite material that resists compressive stress and provides bulk to the composite material. For efficient filling, aggregate should be much smaller than the finished item, but have a wide variety of sizes...
or tar-sprayed chippings to create better road metalling
Metal (pavement)
The term road metal refers to the crushed rock used for road beds, surfaces, 'all-weather' walkways and paths, foundations, and railway embankments, among other things. The use of road metal dates back to antiquity.-History:...
. More recently, oil
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
-based asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
laid on reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...
has become a major road surface, but its use of granite or limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
chippings still recalls McAdam's innovation.
Early life
McAdam was born in AyrAyr
Ayr is a town and port situated on the Firth of Clyde in south-west Scotland. With a population of around 46,000, Ayr is the largest settlement in Ayrshire, of which it is the county town, and has held royal burgh status since 1205...
, Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. He was the youngest of ten children and second son of the Baron of Waterhead. The family name had traditionally been McGregor, but was changed to McAdam (claiming descent from the Biblical Adam) for political reasons in James I
James I of Scotland
James I, King of Scots , was the son of Robert III and Annabella Drummond. He was probably born in late July 1394 in Dunfermline as youngest of three sons...
's reign. He moved to New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
in 1770 and, as a merchant
Merchant
A merchant is a businessperson who trades in commodities that were produced by others, in order to earn a profit.Merchants can be one of two types:# A wholesale merchant operates in the chain between producer and retail merchant...
and prize agent during the American Revolution
American Revolution
The American Revolution was the political upheaval during the last half of the 18th century in which thirteen colonies in North America joined together to break free from the British Empire, combining to become the United States of America...
, made his fortune working at his uncle's counting house
Counting house
A counting house, or compting house, literally is the building, room, office or suite in which a business firm carries on operations, particularly accounting. By a synecdoche, it has come to mean the accounting operations of a firm, however housed...
. He returned to Scotland in 1783 and purchased an estate at Sauchrie, Ayrshire
Ayrshire
Ayrshire is a registration county, and former administrative county in south-west Scotland, United Kingdom, located on the shores of the Firth of Clyde. Its principal towns include Ayr, Kilmarnock and Irvine. The town of Troon on the coast has hosted the British Open Golf Championship twice in the...
.
Road builder
McAdam became a trustee of the Ayrshire Turnpike in 1783 and became increasingly involved with day-to-day road construction over the next 10 years. In 1812 he moved to BristolBristol
Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...
, England and he became general surveyor for the Bristol Corporation in 1804. He put forward his ideas in evidence to Parliamentary
Parliament of the United Kingdom
The Parliament of the United Kingdom of Great Britain and Northern Ireland is the supreme legislative body in the United Kingdom, British Crown dependencies and British overseas territories, located in London...
enquiries in 1810, 1819 and 1823. In two treatise
Treatise
A treatise is a formal and systematic written discourse on some subject, generally longer and treating it in greater depth than an essay, and more concerned with investigating or exposing the principles of the subject.-Noteworthy treatises:...
s written in 1816 and 1819 (Remarks on the Present System of Road-Making and Practical Essay on the Scientific Repair and Preservation of Roads) he argued that roads needed to be raised above the surrounding ground and constructed from layered rocks and gravel in a systematic manner.
McAdam had also been appointed surveyor to the Bristol Turnpike Trust
Turnpike trust
Turnpike trusts in the United Kingdom were bodies set up by individual Acts of Parliament, with powers to collect road tolls for maintaining the principal highways in Britain from the 17th but especially during the 18th and 19th centuries...
in 1816, where he decided to remake the roads under his care with crushed stone
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
bound with gravel on a firm base of large stones. A camber
Camber
Camber may refer to a variety of curvatures and angles:* Camber angle, the angle made by the wheels of a vehicle* Camber thrust in bike technology* In the steel industry, the concavity of rolls...
, making the road slightly convex, ensured rainwater rapidly drained off the road rather than penetrate and damage the road's foundations. This construction method, the greatest advance in road construction since Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
times, became known as "macadamisation", or, more simply, "macadam
Macadam
Macadam is a type of road construction pioneered by the Scotsman John Loudon McAdam in around 1820. The method simplified what had been considered state-of-the-art at that point...
".
The macadam method spread very quickly across the world. The first macadam road in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, the National Road
National Road
The National Road or Cumberland Road was the first major improved highway in the United States to be built by the federal government. Construction began heading west in 1811 at Cumberland, Maryland, on the Potomac River. It crossed the Allegheny Mountains and southwestern Pennsylvania, reaching...
, was completed in the 1830s and most of the main roads in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
were macadamized by the end of the nineteenth century.
Although McAdam was paid £
Pound sterling
The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence...
5,000 for his Bristol Turnpike Trust work and made "Surveyor-General of Metropolitan Roads" in 1820, professional jealousy cut a £5,000 grant for expenses from the Parliament of the United Kingdom
Parliament of the United Kingdom
The Parliament of the United Kingdom of Great Britain and Northern Ireland is the supreme legislative body in the United Kingdom, British Crown dependencies and British overseas territories, located in London...
to £2,000 in 1827. His efficient road-building and management work had revealed the corruption and abuse of road toll
Toll road
A toll road is a privately or publicly built road for which a driver pays a toll for use. Structures for which tolls are charged include toll bridges and toll tunnels. Non-toll roads are financed using other sources of revenue, most typically fuel tax or general tax funds...
s by unscrupulous Turnpike Trusts, many of which were run at a deliberate loss despite high toll receipts.
Death and descendants
McAdam died in MoffatMoffat
Moffat is a former burgh and spa town in Dumfries and Galloway, Scotland, lying on the River Annan, with a population of around 2,500. The most notable building in the town is the Moffat House Hotel, designed by John Adam...
, Dumfriesshire
Dumfriesshire
Dumfriesshire or the County of Dumfries is a registration county of Scotland. The lieutenancy area of Dumfries has similar boundaries.Until 1975 it was a county. Its county town was Dumfries...
, while returning to his home in Hoddesdon
Hoddesdon
Hoddesdon is a town in the English county of Hertfordshire, situated in the Lea Valley. The town grew up as a coaching stop on the route between Cambridge and London. It is located southeast of Hertford, north of Waltham Cross and southwest of Bishop's Stortford. At its height during the 18th...
, Hertfordshire
Hertfordshire
Hertfordshire is a ceremonial and non-metropolitan county in the East region of England. The county town is Hertford.The county is one of the Home Counties and lies inland, bordered by Greater London , Buckinghamshire , Bedfordshire , Cambridgeshire and...
, from his annual summer visit to Scotland. His three sons, and in turn four grandsons, followed him into the profession and assisted with the management of turnpike trusts around the country. His second surviving son, James Nicholl McAdam, the "Colossus of Roads", was knighted for managing turnpike trusts—a knighthood, it is said, previously offered to his father but declined.
External links
- Remarks on the Present System of Road Making by John Loudon McAdam, 1821, from Google Book SearchGoogle Book SearchGoogle Books is a service from Google that searches the full text of books that Google has scanned, converted to text using optical character recognition, and stored in its digital database. The service was formerly known as Google Print when it was introduced at the Frankfurt Book Fair in October...
- John McAdam @about.com
- John Loudon McAdam @maybole.com
- Ayrshire History – James McAdam
- McAdam and other eponymous products @ Ward’s Book of Days
- Electric Scotland Significant Scots – John Loudon McAdam