xxxxxIt was after the discovery of X-rays by Wilhelm Roentgen in 1895, followed soon afterwards by Henri Becquerel’s discovery of radioactivity, that Marie and Pierre Curie began their research into these mysterious rays. In 1898 they carefully measured the radiations emitting from pitchblende (an ore rich in uranium), and discovered two new and more powerful radioactive elements, polonium and radium. The amount they found, however, was miniscule, and they then set out to isolate pure radium in a quantity sufficient to determine its chemical properties. This laboriously and hazardous task took three years to complete, but by 1903 they had isolated a tenth of a gram of pure radium from some eight tons of pitchblende. In that year they, together with the Henri Becquerel, received the Nobel Prize for Physics. In 1906 Pierre Curie was tragically killed in a road accident. Marie was heartbroken, but she continued her research into the chemistry of radioactive elements, and in 1911 was awarded the Nobel Prize for Chemistry. By then a well-known and respected scientist, she developed radiography for medical purposes during the First World War, and then worked to expand the work of her Radium Institutes in Paris and Warsaw. She died of leukaemia in 1935, caused by her prolonged exposure to the radioactive materials she had herself discovered. Given time, the discoveries made by the Curies, refined and expanded, was to bring about a deeper understanding of the unstable atoms that made up these radioactive materials, and led to a new branch of science, that of nuclear physics.

MARIE CURIE   1867 - 1934  (Vb, Vc, E7, G5)

PIERRE CURIE 1859 - 1906  (Va, Vb, Vc, E7)


Marie: by the Parisian photographer Henri Manuel (1874-1947) – Bibliothèque Marguerite Durand, Paris. Pierre: by the French photographer Eugène Pirou (1841-1909). Electrometer: photo ACJC. Shed: date and photographer unknown. Mobile X-Ray Unit: c1915, photographer unknown. Pantheon: drawing and steel engraving by the French brothers Adolphe and Émile Rouargue (1795-1865), 1846. Rutherford: by the Scottish portrait painter Sir Herbert James Gunn (1893-1964), 1932 – National Portrait Gallery, London. Ramsay: by the English portrait painter Mark Richard Milbanke (1875-1927), 1913 – University College, London.

xxxxxIt was in 1898, that the husband and wife team Pierre and Marie Curie, - scientists who had met while working in Paris - discovered polonium and radium, two new radioactive elements found in pitchblende ores. Their research into the phenomena of radiation, conducted over two years, was prompted by Wilhelm Roentgen’s discovery of X-rays - as we have seen - in 1895, and the discovery shortly afterwards of radioactivity by the French physicist Henri Becquerel. After their findings, the Curies, working relentlessly over the next three years, eventually isolated a small quantity of pure radium chlorate in 1902, and the following year, in recognition of their work, were jointly awarded the Nobel Prize for Physics, together with Henri Becquerel. Their painstaking research greatly increased the understanding of the structure and workings of the atom, and paved the way for the modern science of nuclear physics.

xxxxxMarie Curie, originally Maria Sklodowska, was born in Warsaw, then within the Russian Empire. Her father was a local teacher in mathematics and physics, and it was from him that she first acquired her interest in science. After completing her schooling, she worked as a private tutor and governess for a number of years before beginning her studies in physics and mathematics at the Sorbonne (the University of Paris) in 1891. By 1894 she had gained degrees in both subjects and, after a brief holiday in Warsaw, returned to make a study of the magnetic properties of steel. It was at this time that she met Pierre Curie, a young physicist who had already made a name for himself. Among other findings, he had established the phenomenon of piezoelectricity, created when pressure is exerted on certain crystals, and, during his study of the relationship between magnetism and heat, he had established the Curie point, the temperature above which ferromagnetic substances lose their magnetism.

xxxxxThey married in 1895, and the following year, fascinated by the findings of Henri Becquerel, Marie decided to carry out research into these mysterious uranium radiations. At that time her husband was laboratory chief at the Paris Municipal School of Industrial Physics and Chemistry, and she was thus able to set up her laboratory in a draughty but disused storeroom on the premises. Using an electrometer specifically designed to measure a very low electric charge - developed, in fact, by Pierre Curie and his brother Jacques some fifteen years earlier (illustrated) - she carefully measured the radiations emitted from pitchblende, a brownish-black ore known to contain uranium, and soon came to realise that she was obtaining readings that were more intense than could possibly be obtained from the uranium alone. She concluded that an unknown element or elements, small in amount but with a much greater degree of radioactivity (a term she herself coined) must be present in the ore.

xxxxxSuch was the potential importance of this conclusion, that her husband then set aside his research on crystals and joined her in her research. Having removed the uranium from a quantity of pitchblende, they carried out a series of chemical treatments on the residue and in July and December of 1898 discovered two new radioactive elements. They named the first polonium (in honour of Marie’s homeland), and the second radium, after the Latin word for “ray”. In each case, the amount detected was miniscule but, as suspected, both elements were highly radioactive. Compared with uranium, polonium had a level of radioactivity 400 times higher, and radium 900 times higher.

xxxxxMarie announced their findings in December, but the amount obtained of each element was so minute - particularly of radium - that they were unable to prove their existence let alone provide a viable description. Their next task was to isolate pure radium in a quantity sufficient to determine its chemical properties. It was a mammoth, backbreaking and hazardous undertaking which took three years to complete. Marie moved her “laboratory” to what became known as that “miserable old shed” in the school courtyard (illustrated), and had several tons of pitchblende delivered from a silver mine at Joachimsthal in Bohemia. The Austrian government, the mine’s owner, donated a ton to the project, and the Academy of Sciences in Vienna obtained the ore at a reasonable cost. The couple then set about making repeated separations of the various substances in the pitch, some 30 in all, and managed to purify about 20 kilograms of the ore each day. The boiling process made the shed into a hothouse, and their eyes and throats were made sore by the noxious fumes, but they completed the task in 1902. From this vast quantity of pitchblende - estimated at eight tons - they eventually ended up isolating just one tenth of a gram of pure radium chloride, but that was enough to substantiate their claim.

xxxxxMarie submitted her doctoral dissertation on her research in 1903 and, in the same year, she and her husband, together with the French physicist Henri Becquerel, were jointly awarded the Nobel Prize for Physics for the discovery of radioactivity. The following year Pierre was appointed Professor of Physics at the Sorbonne, with Marie as his first assistant. The work they had done, and the discoveries they had made were at last recognised, and the money from their prizes helped to improve their standard of living, but in 1906 tragedy struck. While crossing a Paris street Pierre was run down and killed by a horse-drawn truck at the age of 47. Marie was heartbroken, “an incurably and wretchedly lonely person” as she put it, but she remained determined to continue her research into the chemistry of radioactive materials. In that year she took her husband’s chair at the Sorbonne - the first woman to teach at the university - and in 1910 published her Treatise on Radioactivity. The following year, now recognised as the world’s greatest woman scientist, she was awarded the Nobel Prize for Chemistry for the isolation of pure radium, becoming thereby the only person to date to be awarded two Nobel prizes.

xxxxxWhen the First World War broke out in 1914, together with her daughter Irène, she turned all her efforts to the development of radiography in medicine. As head of the Radiological Service within the International Red Cross, she held courses to teach doctors and medical orderlies how to use the new technique, established some 200 radiology units, and equipped a number of vehicles with X-ray equipment - known as “little Curies”. (The illustration shows her driving one of them.) In the post-war years she continued to develop the work of her Radium Institute, set up in Paris in 1914 to promote research into chemistry, physics and medicine, and she frequently lectured abroad. Two highly successful visits to the United States brought a deal of financial support, enabling her to set up international scholarships for scientific study, and to found the Radium Institute in Warsaw in 1925 - with her sister, Bronislawa, as the director.  

xxxxxMarie Curie’s health began to deteriorate in the late 1920s, and she died in Haute Savoie from leukaemia in July 1934, a disease caused by prolonged exposure to the radioactive materials which she had studied so diligently over so many years. Radium brought her both fame and death. Unaware of the dangers associated with radioactivity, neither she nor her husband had taken any precautions during their research. The extent of her exposure to these harmful rays is borne out by the fact that, even today, her notebooks are too contaminated to handle.

xxxxxIncidentally, in 1905, the year before his tragic death, Pierre Curie was named a member of the French Academy of Science. However, despite his wife’s outstanding scientific achievements, in 1911, the year she was awarded the Nobel Prize for Chemistry, the Academy continued to show its prejudice against women. She failed by two votes to be named a member. Edouard Branly, the French physicist who had assisted Marconi to develop wireless telegraphy, was elected in her place. ……

xxxxx…… After her funeral Marie Curie was interred alongside her husband at the cemetery at Sceaux, in south Paris. In 1995, however, both their remains were transferred to the Pantheon in the heart of the city (illustrated), a mausoleum reserved for the remains of distinguished citizens of France. She was the first and, to date, the only woman to be honoured in this way. The Curie Museum is situated a short distance from the “miserable old shed” where she and her husband worked so hard, and the unit by which radioactivity is measured is called the curie after her. ……

xxxxx…… The Curies had two daughters, both of whom had distinguished careers. In 1935 Irène, a doctor in science, was awarded the Nobel Prize in Chemistry, together with her husband Frédéric Joliot, for the discovery of artificial radioactivity. Eve gained degrees in science and philosophy, but then turned to journalism and writing. Her most celebrated work was the brilliant biography of her mother, published in 1937. ……

xxxxxFollowingxthe work achieved by the Curies, research into radioactivity was continued by the likes of the New Zealand scientist Ernest Rutherford (1871-1937) (illustrated) - who came to be regarded as the father of nuclear physics -, the French chemist Paul Villard (1860-1934), and the English chemist Frederick Soddy (1877-1956). Building upon the discoveries made by the Curies - notably the fact that the atoms of uranium, radium and other heavy elements were unstable - Rutherford showed in 1899 that radioactive material emits more than one kind of ray. He named the two he discovered alpha and beta from the first two letters of the Greek alphabet. And a year later Villard identified a third “gamma” ray. Then in 1902, Rutherford and Soddy, studying the properties of thorium at McGill University in Montreal, discovered that this chemical element decayed at a fixed rate and, over time, changed into a different element by a process that came to be known as atomic transmutation. It was such findings, refined and expanded over the years, that was to create a new field of physics, a branch of science which, for mankind, had the potential of being both very beneficial and enormously destructive.



William Ramsay

xxxxxIt was also in the closing years of the 19th century that advances were made in the discovery of the so-called inert gases, particularly by the Scottish chemist William Ramsay (1852-1916). In 1894, working with the English physicist Lord Rayleigh, he discovered the inert gas argon (Greek for inactive), and helium the following year. Then in 1898, in cooperation with the English chemist Morris Travers, he discovered three other inert gases, krypton, neon and xenon. He was knighted in 1902, and awarded the Nobel Prize for Chemistry in 1904. His major work, The Gases of the Atmosphere, was published in 1896.

xxxxxIt was also at this time, the closing years of the 19th century, that advances were made in the discovery of the so-called inert gases. The pioneer in this field was the Scottish chemist William Ramsay (1852-1916). He was born and educated in Glasgow, and later studied at the University of Tubingen in Germany. In 1880 he became Professor of Chemistry at the University College of Bristol (the forerunner of the city’s university), and appointed principal of the College the following year. From 1887 until 1913 he was Professor of Chemistry at University College, London, and it was here that he made the discoveries that earned him the Nobel Prize for Chemistry in 1904.

xxxxxInx1894, working with the English physicist Lord Rayleigh (1842-1919), he removed from air the various known gases - such oxygen and nitrogen - and discovered a chemically inert gas which made up about one percent of the atmosphere. He called it argon after the Greek word for inactive. Thexfollowing year he isolated helium, and in 1898, in cooperation with the English chemist Morris Travers (1872-1961), he discovered small amounts of three other inert gases in air: krypton (meaning hidden), neon (new) and xenon (stranger). Knighted in 1902, his major work was The Gases of the Atmosphere, published in 1896.

xxxxxIncidentally, Lord Rayleigh, born John William Strutt, wrote a two-volume work entitled The Theory of Sound in 1877/1878, and is remembered today for the Rayleigh scattering, a phenomenon which explains why the sky is blue. …… Morris Travers, known as “Rare Gas Travers”, was appointed director of the Indian Institute of Science in 1906 (on Ramsay’s recommendation), but returned to Britain at the outbreak of the First World War in 1914. He wrote a biography of Sir William Ramsay in 1956.