Julius Robert von Mayer (25 November 1814 – 20 March 1878) was a German
physician
A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...
,
chemist
A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...
, and
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 ...
and one of the founders of
thermodynamics
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of the ...
. He is best known for enunciating in 1841 one of the original statements of the
conservation of energy
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be ''conserved'' over time. This law, first proposed and tested by Émilie du Châtelet, means th ...
or what is now known as one of the first versions of the
first law of thermodynamics
The first law of thermodynamics is a formulation of the law of conservation of energy, adapted for thermodynamic processes. It distinguishes in principle two forms of energy transfer, heat and thermodynamic work for a system of a constant amoun ...
, namely that "energy can be neither created nor destroyed". In 1842, Mayer described the vital
chemical process
In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, and involves a chemical reaction of some ...
now referred to as
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
as the primary source of
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 ...
for any
living creature. His achievements were overlooked and priority for the discovery of the ''
mechanical equivalent of heat
In the history of science, the mechanical equivalent of heat states that motion and heat are mutually interchangeable and that in every case, a given amount of work would generate the same amount of heat, provided the work done is totally converte ...
'' was attributed to
James 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). T ...
in the following year. He also proposed that
plants
Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...
convert light into chemical energy.
Early life
Mayer was born on 25 November 1814 in
Heilbronn
Heilbronn () is a List of cities and towns in Germany, city in northern Baden-Württemberg, Germany, surrounded by Heilbronn (district), Heilbronn District. With over 126,000 residents, it is the sixth-largest city in the state.
From the late Mid ...
,
Württemberg
Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart.
Together with Baden and Hohenzollern, two other historical territories, Würt ...
(
Baden-Württemberg
Baden-Württemberg (; ), commonly shortened to BW or BaWü, is a German state () in Southwest Germany, east of the Rhine, which forms the southern part of Germany's western border with France. With more than 11.07 million inhabitants across a ...
, modern day Germany), the son of a
pharmacist
A pharmacist, also known as a chemist (Commonwealth English) or a druggist (North American and, archaically, Commonwealth English), is a healthcare professional who prepares, controls and distributes medicines and provides advice and instructi ...
. He grew up in Heilbronn. After completing his ''
Abitur
''Abitur'' (), often shortened colloquially to ''Abi'', is a qualification granted at the end of secondary education in Germany. It is conferred on students who pass their final exams at the end of ISCED 3, usually after twelve or thirteen year ...
'', he studied medicine at the
University of Tübingen
The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-Wü ...
, where he was a member of the ''Corps Guestphalia'', a
German Student Corps
Corps (or Korps; "''das ~''" ('' n''), (''sg.''), (''pl.'')) are the oldest still-existing kind of ''Studentenverbindung'', Germany's traditional university corporations; their roots date back to the 15th century. The oldest corps still existi ...
. During 1838 he attained his doctorate as well as passing the ''
Staatsexamen
The ("state examination" or "exam by state"; pl.: ''Staatsexamina'') is a German government licensing examination that future physicians, dentists, teachers, pharmacists, food chemists, psychotherapists and jurists (i.e., lawyers, judges, public ...
''. After a stay in Paris (1839/40) he left as a ship's physician on a
Dutch
Dutch commonly refers to:
* Something of, from, or related to the Netherlands
* Dutch people ()
* Dutch language ()
Dutch may also refer to:
Places
* Dutch, West Virginia, a community in the United States
* Pennsylvania Dutch Country
People E ...
three-mast
sailing ship
A sailing ship is a sea-going vessel that uses sails mounted on masts to harness the power of wind and propel the vessel. There is a variety of sail plans that propel sailing ships, employing square-rigged or fore-and-aft sails. Some ships c ...
for a journey to
Jakarta
Jakarta (; , bew, Jakarte), officially the Special Capital Region of Jakarta ( id, Daerah Khusus Ibukota Jakarta) is the capital and largest city of Indonesia. Lying on the northwest coast of Java, the world's most populous island, Jakarta ...
.
Although he had hardly been interested before this journey in
physical phenomena
Physical may refer to:
*Physical examination, a regular overall check-up with a doctor
*Physical (Olivia Newton-John album), ''Physical'' (Olivia Newton-John album), 1981
**Physical (Olivia Newton-John song), "Physical" (Olivia Newton-John song)
*P ...
, his observation that storm-whipped waves are warmer than the calm sea started him thinking about the
physical law
Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. The term ''law'' has diverse usage in many cases (approximate, accurate, broad, or narrow) a ...
s, in particular about the physical phenomenon of warmth and the question ''whether the directly developed heat alone (the heat of combustion), or the sum of the quantities of heat developed in direct and indirect ways are to be accounted for in the burning process''. After his return in February 1841 Mayer dedicated his efforts to solve this problem.
In 1841 he settled in
Heilbronn
Heilbronn () is a List of cities and towns in Germany, city in northern Baden-Württemberg, Germany, surrounded by Heilbronn (district), Heilbronn District. With over 126,000 residents, it is the sixth-largest city in the state.
From the late Mid ...
and married.
Development of ideas
Even as a young child, Mayer showed an intense interest with various mechanical mechanisms. He was a young man who performed various experiments of the physical and chemical variety. In fact, one of his favorite hobbies was creating various types of electrical devices and air pumps. It was obvious that he was intelligent. Hence, Mayer attended Eberhard-Karls University in May 1832. He studied medicine during his time there.
In 1837, he and some of his friends were arrested for wearing the
couleur
Couleur (from French, meaning ''colour'' in English language, English) is the expression used in Central European ''Studentenverbindungen'' for the various headgear and distinctive ribbons worn by members of these student societies.
There are thr ...
s of a forbidden organization. The consequences for this arrest included a one year expulsion from the college and a brief period of incarceration. This diversion sent Mayer traveling to Switzerland, France, and the
Dutch East Indies
The Dutch East Indies, also known as the Netherlands East Indies ( nl, Nederlands(ch)-Indië; ), was a Dutch colony consisting of what is now Indonesia. It was formed from the nationalised trading posts of the Dutch East India Company, which ...
. Mayer drew some additional interest in mathematics and engineering from his friend Carl Baur through private tutoring. In 1841, Mayer returned to Heilbronn to practice medicine, but physics became his new passion.
In June 1841 he completed his first scientific paper entitled "On the Quantitative and Qualitative Determination of Forces". It was largely ignored by other professionals in the area. Then, Mayer became interested in the area of heat and its motion. He presented a value in numerical terms for the mechanical equivalent of heat. He also was the first person to describe the vital chemical process now referred to as oxidation as the primary source of energy for any living creature.
In 1848 he calculated that in the absence of a source of energy the Sun would cool down in only 5000 years, and he suggested that the impact of meteorites kept it hot.
Since he was not taken seriously at the time, his achievements were overlooked and credit was given to
James 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). T ...
. Mayer almost committed suicide after he discovered this fact. He spent some time in mental institutions to recover from this and the loss of some of his children. Several of his papers were published due to the advanced nature of the physics and chemistry. He was awarded an honorary doctorate in 1859 by the philosophical faculty at the
University of Tübingen
The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-Wü ...
. His overlooked work was revived in 1862 by fellow physicist
John Tyndall
John Tyndall FRS (; 2 August 1820 – 4 December 1893) was a prominent 19th-century Irish physicist. His scientific fame arose in the 1850s from his study of diamagnetism. Later he made discoveries in the realms of infrared radiation and the p ...
in a lecture at the London Royal Institution. In July 1867 Mayer published "Die Mechanik der Wärme." This publication dealt with the mechanics of heat and its motion. On 5 November 1867 Mayer was awarded personal nobility by the
Kingdom of Württemberg
The Kingdom of Württemberg (german: Königreich Württemberg ) was a German state that existed from 1805 to 1918, located within the area that is now Baden-Württemberg. The kingdom was a continuation of the Duchy of Württemberg, which exist ...
(von Mayer) which is the German equivalent of a British knighthood. von Mayer died in Germany in 1878.
After Sadi Carnot stated it for caloric, Mayer was the first person to state the law of the conservation of energy, one of the most fundamental tenets of modern day physics. The law of the conservation of energy states that the total mechanical energy of a system remains constant in any isolated system of objects that interact with each other only by way of forces that are
conservative
Conservatism is a cultural, social, and political philosophy that seeks to promote and to preserve traditional institutions, practices, and values. The central tenets of conservatism may vary in relation to the culture and civilization i ...
.
Mayer's first attempt at stating the conservation of energy was a paper he sent to
Johann Christian Poggendorff
Johann Christian Poggendorff (29 December 1796 – 24 January 1877), was a German physicist born in Hamburg. By far the greater and more important part of his work related to electricity and magnetism. Poggendorff is known for his electrostatic m ...
's ''
Annalen der Physik
''Annalen der Physik'' (English: ''Annals of Physics'') is one of the oldest scientific journals on physics; it has been published since 1799. The journal publishes original, peer-reviewed papers on experimental, theoretical, applied, and mathe ...
'', in which he postulated a conservation of force (''Erhaltungssatz der Kraft''). However, owing to Mayer's lack of advanced training in
physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
, it contained some fundamental mistakes and was not published. Mayer continued to pursue the idea steadfastly and argued with the
Tübingen
Tübingen (, , Swabian: ''Dibenga'') is a traditional university city in central Baden-Württemberg, Germany. It is situated south of the state capital, Stuttgart, and developed on both sides of the Neckar and Ammer rivers. about one in thr ...
physics professor
Johann Gottlieb Nörremberg, who rejected his
hypothesis
A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...
. Nörremberg did, however, give Mayer a number of valuable suggestions on how the idea could be examined experimentally; for example, if
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 ...
transforms into heat energy, water should be warmed by
vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The word comes from Latin ''vibrationem'' ("shaking, brandishing"). The oscillations may be periodic function, periodic, such as the motion of a pendulum ...
.
Mayer not only performed this demonstration, but determined also the quantitative factor of the transformation, calculating the mechanical equivalent of heat. The result of his investigations was published 1842 in the May edition of
Justus von Liebig
Justus Freiherr von Liebig (12 May 1803 – 20 April 1873) was a German scientist who made major contributions to agricultural and biological chemistry, and is considered one of the principal founders of organic chemistry. As a professor at t ...
's ''
Annalen der Chemie und Pharmacie
''Justus Liebigs Annalen der Chemie'' (often cited as just ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebi ...
''. It was translated as ''Remarks on the Forces of Inorganic Nature'' In his booklet ''Die organische Bewegung im Zusammenhang mit dem Stoffwechsel'' (''The Organic Movement in Connection with the Metabolism'', 1845) he specified the numerical value of the mechanical equivalent of heat: at first as 365
kgf KGF or ''kgf'' may refer to:
*Keratinocyte growth factor
*King George's Fields, UK, recreation grounds
*Kolar Gold Fields
*The IATA code for Sary-Arka Airport, Karaganda, Kazakhstan
* ''K.G.F'' (film series), Indian Kannada-language film series
* ...
·m/kcal, later as 425 kgf·m/kcal; the modern values are 4.184
kJ/kcal (426.6 kgf·m/kcal) for the thermochemical calorie and 4.1868 kJ/kcal (426.9 kgf·m/kcal) for the international steam table calorie.
This relation implies that, although work and heat are different forms of energy, they can be transformed into one another. This law is now called the
first law of thermodynamics
The first law of thermodynamics is a formulation of the law of conservation of energy, adapted for thermodynamic processes. It distinguishes in principle two forms of energy transfer, heat and thermodynamic work for a system of a constant amoun ...
, and led to the formulation of the general principle of
conservation of energy
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be ''conserved'' over time. This law, first proposed and tested by Émilie du Châtelet, means th ...
, definitively stated by
Hermann von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz (31 August 1821 – 8 September 1894) was a German physicist and physician who made significant contributions in several scientific fields, particularly hydrodynamic stability. The Helmholtz Association, ...
in 1847.
Mayer's relation
Mayer derived a relation between specific heat at constant pressure and the specific heat at constant volume for an ideal gas. The relation is:
,
where ''C
P,m'' is the
molar specific heat
Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K).
Heat capacity ...
at constant
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 ...
, ''C
V,m'' is the molar specific heat at constant
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 ...
and ''R'' is the
gas constant
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol or . It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per ...
.
Later life
Mayer was aware of the importance of his discovery, but his inability to express himself scientifically led to degrading speculation and resistance from the scientific establishment. Contemporary physicists rejected his principle of conservation of energy, and even acclaimed physicists
Hermann von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz (31 August 1821 – 8 September 1894) was a German physicist and physician who made significant contributions in several scientific fields, particularly hydrodynamic stability. The Helmholtz Association, ...
and
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 ...
viewed his ideas with hostility. The former doubted Mayer's qualifications in physical questions, and a bitter dispute over priority developed with the latter.
In 1848 two of his children died rapidly in succession, and Mayer's
mental health
Mental health encompasses emotional, psychological, and social well-being, influencing cognition, perception, and behavior. It likewise determines how an individual handles stress, interpersonal relationships, and decision-making. Mental health ...
deteriorated. He attempted suicide on 18 May 1850 and was committed to a mental institution. After he was released, he was a broken man and only timidly re-entered public life in 1860. However, in the meantime, his scientific fame had grown and he received a late appreciation of his achievement, although perhaps at a stage where he was no longer able to enjoy it.
He continued to work vigorously as a physician until his death.
Honors
* 1840 Julius von Mayer received the Knight Cross of the
Order of the Crown (Württemberg)
The Order of the Württemberg Crown (''Orden der Württembergischen Krone'') was an order of chivalry in Württemberg.
History
First established in 1702 as the St.-Hubertus-Jagdorden (Order of St Hubert), in 1807 it was renamed the "Ritterorden ...
.
* 1869 Mayer received the
''prix Poncelet''.
* The ''Robert-Mayer-Gymnasium'' and the ''Robert-Mayer-Volks- und Schulsternwarte'' in
Heilbronn
Heilbronn () is a List of cities and towns in Germany, city in northern Baden-Württemberg, Germany, surrounded by Heilbronn (district), Heilbronn District. With over 126,000 residents, it is the sixth-largest city in the state.
From the late Mid ...
bear his name.
In Chemistry, he invented the
Mayer's reagent
Mayer's reagent is an alkaloidal precipitating reagent used for the detection of alkaloids in natural products. Mayer's reagent is freshly prepared by dissolving a mixture of mercuric chloride (1.36 g) and of potassium iodide (5.00 g) in water (1 ...
which is used in detecting alkaloids.
Works
* ''Ueber