Quakers are often prominent in truth-seeking professions. In science, many famous Quakers have contributed to the fields of physics, chemistry and astronomy but Quaker doctors have been instrumental in many important advances over the last few centuries leading to the foundations of modern medicine.

There is an online exhibition about Quakers and Science on the website of British Friends

William Tuke (1733-1822) was the driving force behind the foundation of The Retreat at York, a 'Friends Institute for the mentally afflicted' which changed forever the way that mental illness was treated. The first superintendent at the Retreat was Timothy Maud, Tuke's brother-in-law. Tuke in England and Pinel in France were independently involved in establishing humane treatment for the mentally ill.

John Dalton (1766-1844) was a British chemist and physicist who developed the atomic theory of matter, hence he is known as one of the fathers of modern physics. John was the son of a Quaker weaver, he was educated and then taught at a Quaker school in Cumberland.
(Picture of John Dalton, detail of an engraving by W. Worthington, after a portrait by William Allen, 1814).

William Allen (1770-1843) had wide-ranging scientific, religious and philathropic interests. He was a chemist, an astronomer and a Fellow of the Royal Society who founded Allen and Hanbury's medical and chemical company (still in existence). In 1804 he began his Royal Institution Lectures, and he was involved in establishing schools promoted by his fellow-Quaker Joseph Lancaster, leading to the foundation of the British and Foreign Schools Society.

Thomas Young (1773-1829) was a physicist and was the first to show that light acts as a wave. His famous double-slit experiment established that light was a wave motion, although this conclusion was strongly opposed by contemporary scientists who believed that Newton, who had proposed that light was corpuscular in nature, could not possibly be wrong.

Thomas Hodgkin (1798-1866) was a pathologist and his paper 'On some morbid appearances of the adsorbent glands and spleen' led to the naming of Hodgkin's disease after him. He was concerned for the plight of aborigines, suffering at the hands of European settlers.

Joseph Lister (1827-1912) (Lord Lister) attended two Quaker schools when young. He is remembered for pioneering the use of antiseptics, improving the survival rates from surgery. He was president of the Royal Society. His father, Joseph Jackson Lister (1786-1869) was a founder member of the Microscopical Society and he carried out research into the nature of red corpuscles in mammalian blood. Joseph Jackson Lister was a friend of Thomas Hodgkin.

Arthur Eddington (1882-1944) was a physicist and mathematician who made important contributions to the theory of general relativity. He was a professor of astronomy in Cambridge and a Fellow of the Royal Society.

Kathleen Lonsdale (1903-1971) was a distinguished crystallographer, whose work included confirming the ring structure of benzene. She worked with other scientists including Dorothy Hodgkin to promote peace issues as part of the Pugwash conferences.

Len Lamerton (1915-1999) was one of the founders of radiation biology in Britain. He was Professor of Biophysics as Applied to Medicine, London University 1960-1980 and Dean of the Institute of Cancer Research, London 1967-1977.

• Obituaries written by his colleagues.

Jocelyn Bell Burnell (born 1943) , now Dame Jocelyn, discovered pulsars and worked with Antony Hewish, who won the Nobel Prize for Physics in 1974 for this discovery. Jocelyn was appointed Professor of Physics at the Open University in 1997 (when she was appointed, the number of female professors of physics in the United Kingdom doubled). She was recently a visiting Professor at Princeton University in the USA and now is Dean of Science at Bath University.

G. Gordon Steel (born 1935), my father, spent most of his working life at the Institute of Cancer Research in Surrey. Working with Len Lamerton, he made his name in the field of cell population kinetics and developed methods for measuring the growth rate of tumours. His book "Growth Kinetics of Tumours" (image left) is considered to be a classic, and Radiotherapists throughout the world are trained using the volume entitled "Basic Clinical Radiobiology". Gordon held a Personal Chair as Professor of Radiation Biology as Applied to Radiotherapy (now emeritus) and he served as Editor In Chief of the International Journal of Radiation Biology, until he retired.