Egon Bretscher was a Swiss physicist.

Born near Zurich

Zürich

Zurich is the largest city in Switzerland and the capital of the canton of Zurich. It is located in central Switzerland at the northwestern tip of Lake Zurich...

, Switzerland and educated at the ETH

ETH Zurich

The Swiss Federal Institute of Technology Zurich or ETH Zürich is an engineering, science, technology, mathematics and management university in the City of Zurich, Switzerland....

 there, Bretscher gained a PhD degree in organic chemistry at 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 1926. He returned to Zurich as privat docent to Peter Debye

Peter Debye

Peter Joseph William Debye FRS was a Dutch physicist and physical chemist, and Nobel laureate in Chemistry.-Early life:...

, later moving in 1936 to work in Rutherford’s

Ernest Rutherford

Ernest Rutherford, 1st Baron Rutherford of Nelson OM, FRS was a New Zealand-born British chemist and physicist who became known as the father of nuclear physics...

 laboratory at the Cavendish

Cavendish Laboratory

The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the university's School of Physical Sciences. It was opened in 1874 as a teaching laboratory....

 in Cambridge as a Rockefeller Scholar. Here he switched to research in nuclear physics

Nuclear physics

Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those...

, proposing (with Norman Feather

Norman Feather

Norman Feather FRS FRSE PRSE , was an English physicist.He was Professor of Natural Philosophy at the University of Edinburgh from 1945 to 1975, then Emeritus Professor...

) in 1940 that the 239 isotope of element 94 could be produced from the common isotope of uranium-238

Uranium-238

Uranium-238 is the most common isotope of uranium found in nature. It is not fissile, but is a fertile material: it can capture a slow neutron and after two beta decays become fissile plutonium-239...

 by neutron capture

Neutron capture

Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus. Since neutrons have no electric charge they can enter a nucleus more easily than positively charged protons, which are repelled...

 and that, like U-235

Uranium-235

- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...

, this should be able to sustain a nuclear chain reaction

Nuclear chain reaction

A nuclear chain reaction occurs when one nuclear reaction causes an average of one or more nuclear reactions, thus leading to a self-propagating number of these reactions. The specific nuclear reaction may be the fission of heavy isotopes or the fusion of light isotopes...

. A similar conclusion was independently arrived at by Edwin McMillan

Edwin McMillan

Edwin Mattison McMillan was an American physicist and Nobel laureate credited with being the first ever to produce a transuranium element. He shared the Nobel Prize in Chemistry with Glenn Seaborg in 1951....

 and Philip Abelson

Philip Abelson

Philip Hauge Abelson was an American physicist, a scientific editor, and a science writer.-Life:Abelson was born in 1913 in Tacoma, Washington. He attended Washington State University where he received degrees in chemistry and physics, and the University of California, Berkeley , where he earned...

 at Berkeley Radiation Laboratory. In addition, he devised theoretical chemical procedures for purifying this unknown element away from the parent uranium; this element was named Plutonium

Plutonium

Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...

 by Nicholas Kemmer

Nicholas Kemmer

Nicholas Kemmer FRS, was a Russian born British nuclear physicist who played an integral and an edge leading role in United Kingdom's nuclear programme, and was known as a mentor of Abdus Salam – a Nobel laureate in Physics....

. In 1944 he became a part of the British Mission to the Manhattan Project

Manhattan Project

The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...

 in Los Alamos, New Mexico

Los Alamos, New Mexico

Los Alamos is a townsite and census-designated place in Los Alamos County, New Mexico, United States, built upon four mesas of the Pajarito Plateau and the adjoining White Rock Canyon. The population of the CDP was 12,019 at the 2010 Census. The townsite or "the hill" is one part of town while...

 led by James Chadwick

James Chadwick

Sir James Chadwick CH FRS was an English Nobel laureate in physics awarded for his discovery of the neutron....

, where he made the first measurements on the energy released in fusion processes. His contributions up to 1945 are discussed by Margaret Gowing

Margaret Gowing

Professor Margaret Gowing, CBE, was an English historian.- Overview :Margaret Gowing was involved with the production of several volumes of the officially sponsored History of the Second World War, published by Her Majesty's Stationery Office in conjunction with Longman's, Green and Co...

 in her "Britain and Atomic Energy, 1935-1945", published in 1964.

In 1947 he was invited by John Cockcroft

John Cockcroft

Sir John Douglas Cockcroft OM KCB CBE FRS was a British physicist. He shared the Nobel Prize in Physics for splitting the atomic nucleus with Ernest Walton, and was instrumental in the development of nuclear power....

 to head the Chemistry Division at the newly established Atomic Energy Research Establishment

Atomic Energy Research Establishment

The Atomic Energy Research Establishment near Harwell, Oxfordshire, was the main centre for atomic energy research and development in the United Kingdom from the 1940s to the 1990s.-Founding:...

 at Harwell, Oxfordshire

Harwell, Oxfordshire

Harwell is a village and civil parish in the Vale of White Horse west of Didcot. It was part of Berkshire until the 1974 boundary changes transferred it to Oxfordshire.-Amenities:...

, England and in 1948 succeeded Otto Frisch as head of the Nuclear Physics Division there. Amongst his colleagues were Bruno Pontecorvo

Bruno Pontecorvo

Bruno Pontecorvo was an Italian-born nuclear physicist, an early assistant of Enrico Fermi and then the author of numerous studies in high energy physics, especially on neutrinos. According to Oleg Gordievsky and Pavel Sudoplatov , Pontecorvo was also a Soviet agent...

 (in the Nuclear Physics Division) and Klaus Fuchs

Klaus Fuchs

Klaus Emil Julius Fuchs was a German theoretical physicist and atomic spy who in 1950 was convicted of supplying information from the American, British and Canadian atomic bomb research to the USSR during and shortly after World War II...

 (head of the Theoretical Physics Division). He was awarded a CBE on retirement from Harwell and died in Switzerland in 1973.

He used to joke that his main contribution to physics occurred in the 1920s, when he was climbing with another student Felix Bloch

Felix Bloch

Felix Bloch was a Swiss physicist, working mainly in the U.S.-Life and work:Bloch was born in Zürich, Switzerland to Jewish parents Gustav and Agnes Bloch. He was educated there and at the Eidgenössische Technische Hochschule, also in Zürich. Initially studying engineering he soon changed to physics...

 in the Swiss Alps

Swiss Alps

The Swiss Alps are the portion of the Alps mountain range that lies within Switzerland. Because of their central position within the entire Alpine range, they are also known as the Central Alps....

. Bloch slipped over an icy edge but was saved, as he fell, by the rope joining him to Bretscher. The latter's swift action in driving his ice axe into the ice prevented their combined demise. Bloch later won the Nobel Prize

Nobel Prize

The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

 for physics for his discovery of nuclear magnetic resonance

Nuclear magnetic resonance

Nuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...

.

Of his three sons Mark

Mark Bretscher

Mark Bretscher is a British biological scientist and Fellow of the Royal Society. He works at the Medical Research Council Laboratory of Molecular Biology in Cambridge, United Kingdom...

 and Anthony

Anthony P. Bretscher

Anthony P. Bretscher is a cell biologist and is currently serving as the associate director of the Weill Institute for Cell and Molecular Biology at Cornell University...

 are cell biologists, whilst Peter is an immunologist.