Jan or Johann Josef Loschmidt (March 15, 1821 - July 8, 1895) who referred to himself mostly as 'Josef' (omitting his first name), was a notable Austrian scientist who performed groundbreaking work in chemistry, physics (thermodynamics, optics, electrodynamics) and crystal forms. March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... The coronation banquet for George IV 1821 was a common year starting on Monday (see link for calendar). ... July 8 is the 189th day of the year (190th in leap years) in the Gregorian Calendar, with 176 days remaining. ... 1895 (MDCCCXCV) was a common year starting on Tuesday (see link for calendar) of the Gregorian calendar (or a common year starting on Thursday of the 12-day-slower Julian calendar). ... Chemistry (from Greek χημεία khemeia[1] meaning alchemy) is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals. ... The first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density. ... Thermodynamics (from the Greek thermos meaning heat and dynamics meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... Table of Opticks, 1728 Cyclopaedia Optics ( appearance or look in ancient Greek) is a branch of physics that describes the behavior and properties of light and the interaction of light with matter. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ... For other senses of this word, see crystal (disambiguation). ...

Born of poor Bohemian farming stock in Počerny (Putschirn), now part of Karlovy Vary, Czech Republic, Loschmidt became professor of physical chemistry at the University of Vienna in 1868. Flag of Bohemia Bohemia (Czech: ; German: ) is a historical region in central Europe, occupying the western and middle thirds of the Czech Republic. ... Karlovy Vary   (German: ), also known in English as Carlsbad, is a spa city situated in the western part of the Czech Republic on the confluence of the OhÅ™e and Teplá rivers. ... Physical Chemistry is the combined science of physics, chemistry, thermodynamics, and quantum mechanics which functions to provide molecular-level interpretations of observed macroscopic phenomena. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... 1868 (MDCCCLXVIII) was a leap year starting on Wednesday (see link for calendar) of the Gregorian calendar or a leap year starting on Friday of the 12-day-slower Julian calendar. ...

He had two early mentors. The first was a Bohemian priest, Adalbert Czech, who persuaded Loschmidt's parents to send young Josef to high school in the Piarist monastery in Schlackenwerth and, in 1837, to advanced high-school classes in Prague. The Pauline Congregation of the Mother of God or short Piarists is name of a Catholic educational order, the clerici regulares scholarum piarum, the , founded by Joseph Calasanza (Josephus a Matre Dei) at Rome in the beginning of the 16th century. ... The Old Square Ostrov, formerly Ostrov nad Ohří (German: Schlackenwerth), is a town in the Carlsbad Region, Czech Republic. ... This article or section does not cite its references or sources. ...

This was followed by two years of philosophy and mathematics at Prague's Charles University, where Loschmidt met his second important mentor. This was the philosophy professor Franz Exner, whose eyesight was failing, and who asked Loschmidt to be his personal reader. Exner was known for his innovative school reforms, which included promoting mathematics and science as important subjects. He suggested to Loschmidt, who became a close personal friend, that he apply mathematics to psychological phenomena. In the process of doing this, he became a very able mathematician. The Charles University of Prague (also simply University of Prague; Czech: Univerzita Karlova; Latin: Universitas Carolina) is the oldest and most prestigious Czech university and among the oldest universities in Europe, being founded in 1340s (for the exact year, see below). ...

In 1856, while still a secondary school teacher, Loschmidt determined the size of the molecules in air. ^{[citation needed]} 1856 was a leap year starting on Tuesday (see link for calendar). ... In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds [1] [2] [3] [4] [5]. Chemical substances are not infinitely divisible into smaller fractions of the same substance: a molecule is generally considered the smallest particle of a pure...

His 1861 booklet, Chemische Studien ("chemical studies"), proposed two-dimensional representations for over 300 molecules in a style [1] remarkably similar to that used by modern chemists. Among these were cyclic molecules such as benzene (C₆H₆ (A.K.A. benzol), and related triazines. Loschmidt's work appeared four years before that of Kekulé, who is better known and is generally credited with the discovery of benzene's cyclic structure. This may be an instance of the Matthew effect. 1861 is a common year starting on Tuesday. ... In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds [1] [2] [3] [4] [5]. Chemical substances are not infinitely divisible into smaller fractions of the same substance: a molecule is generally considered the smallest particle of a pure... Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... Benzene, C6H6, PhH, or benzol is a colorless and flammable liquid with a pleasant, sweet smell. ... A triazine is one of three organic chemicals, isomeric with each other, whose empirical formula is C3H3N3. ... Friedrich August Kekulé von Stradonitz Friedrich August Kekulé von Stradonitz (September 7, 1829 – July 13, 1896) was a German organic chemist. ... The Matthew effect may refer to related ideas depending on context: // Biblical Matthew effect alludes to a line spoken by the Master in Jesuss parable of the talents in the Christian Bible: For unto every one that hath shall be given, and he shall have abundance: but from him...

In 1865, Loschmidt was the first to determine the number of molecules of an ideal gas in 1 cm³. This is now known as the "Loschmidt number" L = 2.687 × 10¹⁹ cm^-3.^{[citation needed]} 1865 (MDCCCLXV) is a common year starting on Sunday. ... An ideal gas or perfect gas is a hypothetical gas consisting of identical particles of negligible volume, with no intermolecular forces. ... In chemistry and physics, the Loschmidt number is the number density of an ideal gas at standard temperature and pressure, . It is named after the Austrian chemist Johann Josef Loschmidt, who calculated, in 1865, the number of molecules of such a gas in one cubic centimeter. ...

Later, using Avogadro's result that any gas under the same conditions has the same number of molecules per Mole (unit), Loschmidt determined that number, now called Avogadro's number as being 6.023 × 10²³ molecules. This is why on rare occasions this "Avogadro number" is called the "Loschmidt number" in English (in German, though, "Loschmidt'sche Zahl" is the commonly used name). Count Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e Cerreto, (Turin August 9, 1776 - July 9, 1856) was a great Italian scientist. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... Avogadros number, also called Avogadros constant (NA), named after Amedeo Avogadro, is formally defined to be the number of carbon-12 atoms in 12 grams (0. ...

Loschmidt and his younger university colleague Ludwig Boltzmann became good friends. His critique of Boltzmann's attempt to derive the second law of thermodynamics from kinetic theory became famous as the "reversibility paradox". It led Boltzmann to his statistical concept of entropy as a logarithmic tally of the number of microscopic states corresponding to a given thermodynamic state. Ludwig Eduard Boltzmann (Vienna, Austrian Empire, February 20, 1844 – Duino near Trieste, September 5, 1906) was an Austrian physicist famous for his founding contributions in the fields of statistical mechanics and statistical thermodynamics. ... The second law of thermodynamics is an expression of the universal law of increasing entropy. ... Kinetic theory attempts to explain macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion. ... Loschmidts paradox, also known as the reversibility paradox, is the objection that it should not be possible to deduce an irreversible process from time-symmetric dynamics. ... Ice melting - classic example of entropy increasing[1] described in 1862 by Rudolf Clausius as an increase in the disgregation of the molecules of the body of ice. ... This article needs to be cleaned up to conform to a higher standard of quality. ...

Loschmidt retired from university in 1891 and died in 1895 in Vienna. His only child had died before him at the age of ten. 1891 (MDCCCXCI) was a common year starting on Thursday (see link for calendar). ... 1895 (MDCCCXCV) was a common year starting on Tuesday (see link for calendar) of the Gregorian calendar (or a common year starting on Thursday of the 12-day-slower Julian calendar). ... Inhabitants according to official census figures: 1800 to 2005 Vienna in 1858 Vienna (German: Wien ) is the capital of Austria, and also one of the nine States of Austria. ...

References

• Peter M. Schuster: From Curiosity to Passion: Loschmidt's Route from Philosophy to Natural Science, in: W. Fleischhacker and T. Schönfeld (Editors): Pioneering Ideas for the Physical and Chemical Sciences, Proceedings of the Josef Loschmidt Symposium, held in Vienna, Austria, June 25-27, 1995; Plenum Press, 1997, New York. - ISBN 0-306-45684-2

• John Buckingham: Chasing the Molecule; Sutton Publishing, 2004, Gloucestershire. - ISBN 0-7509-3345-3

External links

• http://www.physicstoday.org/pt/vol-54/iss-3/p45.html
• http://scienceweek.com/2004/rmps-15.htm
• http://www.uh.edu/engines/epi1858.htm
• http://www.loschmidt.cz/
• http://www.ch.ic.ac.uk/rzepa/loschmidt/