James David Forbes
Encyclopedia
James David Forbes was a Scottish physicist and glaciologist who worked extensively on the conduction of heat
and seismology
. Forbes was a resident of Edinburgh
for most of his life, educated at the University
and a professor there from 1833 until he became principal of the United College of St. Andrews in 1859.
He invented the seismometer
in 1842.
in Edinburgh
, the fourth son of Sir William Forbes, 7th Baronet, of Monymusk
and Pitsligo (1773–1828) and Williamina Belches of Invermay
. His brothers were the advocate
and agriculturalist Sir John Stuart Hepburn Forbes of Fettercairn and Pitsligo and the banker Charles Forbes.
He entered the University of Edinburgh
in 1825, and soon afterwards began to contribute papers to the Edinburgh Philosophical Journal anonymously under the signature "Δ". At the age of nineteen he became a fellow of the Royal Society of Edinburgh
, and in 1832 he was elected to the Royal Society of London. A year later he was appointed professor of natural philosophy in Edinburgh University, in succession to Sir John Leslie
and in competition with Sir David Brewster
, and during his tenure of that office, which he did not give up till 1860, he not only proved himself an active and efficient teacher, but also did much to improve the internal conditions of the university. In 1859 he was appointed successor to Brewster in the principalship of the United College of St. Andrews, a position which he held until his death at Clifton in 1868.
As a scientific investigator he is best known for his researches on heat and on glaciers. Between 1836 and 1844 he published in the Trans. Roy. Soc. Ed. four series of "Researches on Heat," in the course of which he demonstrated that tourmaline
would polarize infrared
thermal radiation
, by transmission through a bundle of thin mica plates inclined to the transmitted ray, and by reflection from the multiplied surfaces of a pile of mica
plates placed at the polarizing angle, and also its circular polarization
by two internal reflections in rhombs
of rock salt. His work won him the Rumford Medal
of the Royal Society in 1838, and in 1843 he received its Royal Medal
for a paper on the "Transparency of the Atmosphere and the Laws of Extinction of the Sun's Rays passing through it."
In 1846 he began experiments on the temperature of the earth at different depths and in different soils near Edinburgh, which yielded determinations of the thermal conductivity of trap-tufa, sandstone
and pure loose sand
. Towards the end of his life he was occupied with experimental inquiries into the laws of the conduction of heat in iron bars, and his last piece of work was to show that the thermal conductivity of iron diminishes with increase of temperature.
His attention was directed to the question of the flow of glaciers in 1840 when he met Louis Agassiz
at the Glasgow meeting of the British Association, and in subsequent years he made several visits to Switzerland
, where he was particularly impressed by Bernhard Studer's
theories, and also to Norway
for the purpose of obtaining accurate data. His observations led him to the view that a glacier is an imperfect fluid or a viscous body which is urged down slopes of a certain inclination by the mutual pressure of its parts, and involved him in some controversy with Tyndall and others both as to priority and to scientific principle.
During these expeditions, he made many measurements of the boiling point
of water
at various altitudes. This data set, published in 1857, is often known in statistics
as Forbes' data, its utility being that:
Forbes was also interested in geology
, and published memoirs on the thermal springs of the Pyrenees
, on the extinct volcanoes of the Vivarais (Ardêche
), on the geology of the Cuchullin and Eildon hills, etc. In addition to about 150 scientific papers, he wrote Travels through the Alps of Savoy and Other Parts of the Pennine Chain, with Observations on the Phenomena of Glaciers (1843); Norway and its Glaciers (1853); Occasional Papers on the Theory of Glaciers (1859); A Tour of Mont Blanc and Monte Rosa (1855). He was also the author (1852) of the "Dissertation on the Progress of Mathematical and Physical Science," published in the 8th edition of the Encyclopædia Britannica
.
The Forbes River and Forbes Glacier
s in New Zealand are named after him as is Aiguille Forbes between the Glacier d'Argentiere and the Glacier du Tour above Chamonix.
Heat conduction
In heat transfer, conduction is a mode of transfer of energy within and between bodies of matter, due to a temperature gradient. Conduction means collisional and diffusive transfer of kinetic energy of particles of ponderable matter . Conduction takes place in all forms of ponderable matter, viz....
and seismology
Seismology
Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic,...
. Forbes was a resident of Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
for most of his life, educated at the University
University of Edinburgh
The University of Edinburgh, founded in 1583, is a public research university located in Edinburgh, the capital of Scotland, and a UNESCO World Heritage Site. The university is deeply embedded in the fabric of the city, with many of the buildings in the historic Old Town belonging to the university...
and a professor there from 1833 until he became principal of the United College of St. Andrews in 1859.
He invented the seismometer
Seismometer
Seismometers are instruments that measure motions of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources...
in 1842.
Life and work
Forbes was born at 86 George StreetGeorge Street, Edinburgh
Situated to the north of Princes Street, George Street is a major street in the centre of Edinburgh, the capital of Scotland. Laid out from 1767 as part of James Craig's plan for the New Town, George Street was named in honour of King George III.-Geography:...
in Edinburgh
Edinburgh
Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
, the fourth son of Sir William Forbes, 7th Baronet, of Monymusk
Monymusk
Monymusk is a planned village in the Marr area of Aberdeenshire, Scotland which was almost entirely rebuilt in 1840, although its history dates back to 1170.It is a site for fishing on the nearby River Don.-External links:* *...
and Pitsligo (1773–1828) and Williamina Belches of Invermay
Invermay
Invermay is a diffuse settlement in Perth and Kinross, Scotland. It is situated approximately 2 km southeast of Forteviot on the Water of May, some 8 km southwest of Perth.An early medieval freestanding cross was once located at Invermay...
. His brothers were the advocate
Advocate
An advocate is a term for a professional lawyer used in several different legal systems. These include Scotland, South Africa, India, Scandinavian jurisdictions, Israel, and the British Crown dependencies of Jersey, Guernsey and the Isle of Man...
and agriculturalist Sir John Stuart Hepburn Forbes of Fettercairn and Pitsligo and the banker Charles Forbes.
He entered the University of Edinburgh
University of Edinburgh
The University of Edinburgh, founded in 1583, is a public research university located in Edinburgh, the capital of Scotland, and a UNESCO World Heritage Site. The university is deeply embedded in the fabric of the city, with many of the buildings in the historic Old Town belonging to the university...
in 1825, and soon afterwards began to contribute papers to the Edinburgh Philosophical Journal anonymously under the signature "Δ". At the age of nineteen he became a fellow of the Royal Society of Edinburgh
Royal Society of Edinburgh
The Royal Society of Edinburgh is Scotland's national academy of science and letters. It is a registered charity, operating on a wholly independent and non-party-political basis and providing public benefit throughout Scotland...
, and in 1832 he was elected to the Royal Society of London. A year later he was appointed professor of natural philosophy in Edinburgh University, in succession to Sir John Leslie
John Leslie (physicist)
Sir John Leslie was a Scottish mathematician and physicist best remembered for his research into heat.Leslie gave the first modern account of capillary action in 1802 and froze water using an air-pump in 1810, the first artificial production of ice.In 1804, he experimented with radiant heat using...
and in competition with Sir David Brewster
David Brewster
Sir David Brewster KH PRSE FRS FSA FSSA MICE was a Scottish physicist, mathematician, astronomer, inventor, writer and university principal.-Early life:...
, and during his tenure of that office, which he did not give up till 1860, he not only proved himself an active and efficient teacher, but also did much to improve the internal conditions of the university. In 1859 he was appointed successor to Brewster in the principalship of the United College of St. Andrews, a position which he held until his death at Clifton in 1868.
As a scientific investigator he is best known for his researches on heat and on glaciers. Between 1836 and 1844 he published in the Trans. Roy. Soc. Ed. four series of "Researches on Heat," in the course of which he demonstrated that tourmaline
Tourmaline
Tourmaline is a crystal boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gem comes in a wide variety of colors...
would polarize infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
thermal radiation
Thermal radiation
Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation....
, by transmission through a bundle of thin mica plates inclined to the transmitted ray, and by reflection from the multiplied surfaces of a pile of mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...
plates placed at the polarizing angle, and also its circular polarization
Circular polarization
In electrodynamics, circular polarization of an electromagnetic wave is a polarization in which the electric field of the passing wave does not change strength but only changes direction in a rotary type manner....
by two internal reflections in rhombs
Rhombus
In Euclidean geometry, a rhombus or rhomb is a convex quadrilateral whose four sides all have the same length. The rhombus is often called a diamond, after the diamonds suit in playing cards, or a lozenge, though the latter sometimes refers specifically to a rhombus with a 45° angle.Every...
of rock salt. His work won him the Rumford Medal
Rumford Medal
The Rumford Medal is awarded by the Royal Society every alternating year for "an outstandingly important recent discovery in the field of thermal or optical properties of matter made by a scientist working in Europe". First awarded in 1800, it was created after a 1796 donation of $5000 by the...
of the Royal Society in 1838, and in 1843 he received its Royal Medal
Royal Medal
The Royal Medal, also known as The Queen's Medal, is a silver-gilt medal awarded each year by the Royal Society, two for "the most important contributions to the advancement of natural knowledge" and one for "distinguished contributions in the applied sciences" made within the Commonwealth of...
for a paper on the "Transparency of the Atmosphere and the Laws of Extinction of the Sun's Rays passing through it."
In 1846 he began experiments on the temperature of the earth at different depths and in different soils near Edinburgh, which yielded determinations of the thermal conductivity of trap-tufa, sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and pure loose sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
. Towards the end of his life he was occupied with experimental inquiries into the laws of the conduction of heat in iron bars, and his last piece of work was to show that the thermal conductivity of iron diminishes with increase of temperature.
His attention was directed to the question of the flow of glaciers in 1840 when he met Louis Agassiz
Louis Agassiz
Jean Louis Rodolphe Agassiz was a Swiss paleontologist, glaciologist, geologist and a prominent innovator in the study of the Earth's natural history. He grew up in Switzerland and became a professor of natural history at University of Neuchâtel...
at the Glasgow meeting of the British Association, and in subsequent years he made several visits to Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, where he was particularly impressed by Bernhard Studer's
Bernhard Studer
Bernhard Studer , Swiss geologist, was born at Büren, near Bern.Although educated as a clergyman, he became so interested in geology at the university of Göttingen that he devoted his life to its pursuit...
theories, and also to Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
for the purpose of obtaining accurate data. His observations led him to the view that a glacier is an imperfect fluid or a viscous body which is urged down slopes of a certain inclination by the mutual pressure of its parts, and involved him in some controversy with Tyndall and others both as to priority and to scientific principle.
During these expeditions, he made many measurements of the boiling point
Boiling point
The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
of water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
at various altitudes. This data set, published in 1857, is often known in statistics
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
as Forbes' data, its utility being that:
- It illustrates how a curvilinear relationship between a dependent and independent variableIndependent variableThe terms "dependent variable" and "independent variable" are used in similar but subtly different ways in mathematics and statistics as part of the standard terminology in those subjects...
can be transformed into a linear modelLinear modelIn statistics, the term linear model is used in different ways according to the context. The most common occurrence is in connection with regression models and the term is often taken as synonymous with linear regression model. However the term is also used in time series analysis with a different...
by knowledge of the physical phenomenon observed. - It emphasises the importance of residuals analysis in linear regressionLinear regressionIn statistics, linear regression is an approach to modeling the relationship between a scalar variable y and one or more explanatory variables denoted X. The case of one explanatory variable is called simple regression...
as the residuals manifest an outlierOutlierIn statistics, an outlier is an observation that is numerically distant from the rest of the data. Grubbs defined an outlier as: An outlying observation, or outlier, is one that appears to deviate markedly from other members of the sample in which it occurs....
that is not apparent in a visual inspection of the raw data.
Forbes was also interested in geology
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
, and published memoirs on the thermal springs of the Pyrenees
Pyrenees
The Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain...
, on the extinct volcanoes of the Vivarais (Ardêche
Ardèche
Ardèche is a department in south-central France named after the Ardèche River.- History :The area has been inhabited by humans at least since the Upper Paleolithic, as attested by the famous cave paintings at Chauvet Pont d'Arc. The plateau of the Ardeche River has extensive standing stones ,...
), on the geology of the Cuchullin and Eildon hills, etc. In addition to about 150 scientific papers, he wrote Travels through the Alps of Savoy and Other Parts of the Pennine Chain, with Observations on the Phenomena of Glaciers (1843); Norway and its Glaciers (1853); Occasional Papers on the Theory of Glaciers (1859); A Tour of Mont Blanc and Monte Rosa (1855). He was also the author (1852) of the "Dissertation on the Progress of Mathematical and Physical Science," published in the 8th edition of the Encyclopædia Britannica
Encyclopædia Britannica
The Encyclopædia Britannica , published by Encyclopædia Britannica, Inc., is a general knowledge English-language encyclopaedia that is available in print, as a DVD, and on the Internet. It is written and continuously updated by about 100 full-time editors and more than 4,000 expert...
.
The Forbes River and Forbes Glacier
Forbes Glacier
Forbes Glacier is a glacier which flows west into the northeast corner of Square Bay, on the west coast of Graham Land. It is 10 nautical miles long, 4 nautical miles wide in its central part, and narrows to 2 nautical miles at its mouth...
s in New Zealand are named after him as is Aiguille Forbes between the Glacier d'Argentiere and the Glacier du Tour above Chamonix.