John Herapath (30 May 1790 – 24 February 1868) was an

English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...

who gave a partial account of the

kinetic theory of gases Kinetic (Ancient Greek: κίνησις “kinesis”, movement or to move) may refer to: * Kinetic theory, describing a gas as particles in random motion * Kinetic energy, the energy of an object that it possesses due to its motion Art and enter ...

in 1820 though it was neglected by the scientific community at the time. He was the cousin of William Herapath, the chemist and

William Bird Herapath Dr William Bird Herapath FRS FRSE FRCS (28 February 1820 – 12 October 1868) was an English surgeon and chemist known for his discovery of Herapathite. Life He was born in Bristol, the eldest son of William Herapath, Professor of Chemistry a ...

, the physician who discovered

herapathite Herapathite, or iodoquinine sulfate, is a chemical compound whose crystals are dichroic and thus can be used for polarizing light. It was discovered in 1852 by William Bird Herapath, a Bristol surgeon and chemist. One of his pupils found that add ...

. In 1847 he published an early textbook on

mathematical physics Mathematical physics refers to the development of mathematics, mathematical methods for application to problems in physics. The ''Journal of Mathematical Physics'' defines the field as "the application of mathematics to problems in physics and t ...

Kinetic theory

Herapath's scientific interests started with an attempt to provide a mechanistic explanation for

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

. Motivated by his search for a mechanical explanation of gravitation, he started to consider how a system of colliding particles could give rise to ''

action at a distance In physics, action at a distance is the concept that an object can be affected without being physically touched (as in mechanical contact) by another object. That is, it is the non-local interaction of objects that are separated in space. Non-c ...

''. In considering the effect of the high

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

s near the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

on his ''gravific particles'' he was led to a relationship between temperature and particle

velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...

. Herapath postulated that the

momentum In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass an ...

of a particle in a

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

is a measure of the

absolute temperature Thermodynamic temperature is a quantity defined in thermodynamics as distinct from kinetic theory or statistical mechanics. Historically, thermodynamic temperature was defined by Kelvin in terms of a macroscopic relation between thermodynamic wor ...

of the gas. He used momentum, rather than the

kinetic energy In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its accele ...

on which the later established theory is based, as it seemed to him to avoid some difficulties around whether

elastic collision In physics, an elastic collision is an encounter (collision) between two bodies in which the total kinetic energy of the two bodies remains the same. In an ideal, perfectly elastic collision, there is no net conversion of kinetic energy into o ...

s were possible between indivisible

atom Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and ...

s. Apparently ignorant of

Daniel Bernoulli Daniel Bernoulli FRS (; – 27 March 1782) was a Swiss mathematician and physicist and was one of the many prominent mathematicians in the Bernoulli family from Basel. He is particularly remembered for his applications of mathematics to mechan ...

's work, he was led to the incorrect, but suggestive, relationship that expresses the product of

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

''P'' and

volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). The de ...

''V'' as proportional to the square of his ''true temperature''. The correct relationship is proportional to the absolute temperature, not its square, the error arising from his identification of momentum, rather than

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat a ...

, with temperature. * He submitted his ideas in a paper to the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

in 1820 where it was

peer review Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review ...

ed by Sir

Humphry Davy Sir Humphry Davy, 1st Baronet, (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several elements for t ...

. Davy had already sympathised with the view that heat was associated with

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

motion rather than with

Joseph Black Joseph Black (16 April 1728 – 6 December 1799) was a Scottish physicist and chemist, known for his discoveries of magnesium, latent heat, specific heat, and carbon dioxide. He was Professor of Anatomy and Chemistry at the University of Glas ...

caloric theory The caloric theory is an obsolete scientific theory that heat consists of a self-repellent fluid called caloric that flows from hotter bodies to colder bodies. Caloric was also thought of as a weightless gas that could pass in and out of pores i ...

heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...

but he rejected Herapath's paper with some coolness, uncomfortable with the implication that there was an

absolute zero Absolute zero is the lowest limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvin. The fundamental particles of nature have minimum vibration ...

of temperature at which all

motion In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...

ceased. Davy may also have had some distaste for the mechanistic Newtonian picture, influenced as he was by the more

holistic Holism () is the idea that various systems (e.g. physical, biological, social) should be viewed as wholes, not merely as a collection of parts. The term "holism" was coined by Jan Smuts in his 1926 book ''Holism and Evolution''."holism, n." OED Onl ...

philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...

of the

Romantic movement Romanticism (also known as the Romantic movement or Romantic era) was an artistic, literary, musical, and intellectual movement that originated in Europe towards the end of the 18th century, and in most areas was at its peak in the approximate ...

. *

James Prescott Joule James Prescott Joule (; 24 December 1818 11 October 1889) was an English physicist, mathematician and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). Th ...

presented a short account of the work in 1848. Meanwhile, Herapath maintained a campaign against Davy and the Royal Society in the correspondence pages of ''

The Times ''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper ''The Sunday Times'' (fou ...

'' newspaper.

Great Comet of 1831

On 7 January 1831 Herapath was on

Hounslow Heath Hounslow Heath is a local nature reserve in the London Borough of Hounslow and at a point borders Richmond upon Thames. The public open space, which covers , is all that remains of the historic Hounslow Heath which covered more than . The prese ...

when he sighted a

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

. Due to its brilliance, it is one of the

great comet A great comet is a comet that becomes exceptionally bright. There is no official definition; often the term is attached to comets such as Halley's Comet, which during certain appearances are bright enough to be noticed by casual observers who ar ...

s. The comet was also observed by Thomas Glanville Taylor at the

Madras Observatory The Madras Observatory was an astronomical observatory which had its origins in a private observatory set up by William Petrie in 1786 and later moved and managed by the British East India Company from 1792 in Madras (now known as Chennai). The ...

''Railway Journal''

In 1835 Herapath became editor of ''The Railway Magazine'', which underwent four changes of name during the boom years of railways to become Herapath's ''Railway Journal'' in January 1894. It is now published as ''

Railway Gazette International ''Railway Gazette International'' is a monthly business magazine and news website covering the railway, metro, light rail and tram industries worldwide. Available by annual subscription, the magazine is read in over 140 countries by transport p ...

'', and is not to be confused with ''

The Railway Magazine ''The Railway Magazine'' is a monthly British railway magazine, aimed at the railway enthusiast market, that has been published in London since July 1897. it was, for three years running, the railway magazine with the largest circulation in t ...

'' which commenced publication in 1897. This gave him some limited opportunity to publish his scientific ideas. In 1836, he published a calculation of the

mean There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value (magnitude and sign) of a given data set. For a data set, the ''arithme ...

molecular

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quanti ...

in a gas based on his kinetic theory and hence the

speed of sound The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At , the speed of sound in air is about , or one kilometre in or one mile in . It depends strongly on temperature as w ...

. Joule reproduced his results but is usually incorrectly credited as the originator. The name changes were - *''Railway magazine'' May 1835-Feb. 1836 *''Railway magazine and annals of science'' Mar. 1836-Aug. 1839 *''Railway magazine and steam navigation journal'' Mar.-Aug. 1839 *''Railway magazine and commercial journal'' Aug. 17, 1839-Dec. 1840 *''Herapath's railway magazine, commercial journal, and scientific review'' Jan. 1841-Dec. 1842 *''Herapath's railway and commercial journal'' Jan. 1843-Dec. 1845 The editions from 1839 to 1895 can be viewed in the National ArchivesNational Archives list of records held 1839-1895
/ref> and several issues are also available as e-books, e.g
18371836-1839
and several in Google books.

Later work

He revised his theories in the 1840s, largely based on the experimental work of Thomas Graham and

Henri Victor Regnault Henri Victor Regnault (21 July 1810 – 19 January 1878) was a French chemist and physicist best known for his careful measurements of the thermal properties of gases. He was an early thermodynamicist and was mentor to William Thomson in ...

. * 1847
Mathematical Physics; or, the Mathematical Principles of Natural Philosophy, the causes of heat, gaseous elasticity, gravitation, and other great phenomena of nature
Whittaker and company via

HathiTrust HathiTrust Digital Library is a large-scale collaborative repository of digital content from research libraries including content digitized via Google Books and the Internet Archive digitization initiatives, as well as content digitized locally ...

Herapath died at Catford Bridge,

Lewisham Lewisham () is an area of southeast London, England, south of Charing Cross. It is the principal area of the London Borough of Lewisham, and was within the Historic counties of England, historic county of Kent until 1889. It is identified i ...

on 24 February 1868 and was buried at

West Norwood Cemetery West Norwood Cemetery is a rural cemetery in West Norwood in London, England. It was also known as the South Metropolitan Cemetery. One of the first private landscaped cemeteries in London, it is one of the " Magnificent Seven" cemeteries of L ...

References

External links

* Dave Levermore (2001
Neglected Pioneers: John Herapath
from

University of Maryland The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public land-grant research university in College Park, Maryland. Founded in 1856, UMD is the flagship institution of the University System of M ...