Wednesday, 25 June 2014
Carlo Matteucci (June 21, 1811 - June 25, 1868) was an Italian physicist and neurophysiologist who was a pioneer in the study of bioelectricity. Carlo Matteucci was born at Forlì, in the province of Romagna, to Vincenzo Matteucci, a physician, and Chiara Folfi. He studied mathematics at the University of Bologna from 1825 to 1828, receiving his doctorate in 1829. From 1829 to 1831 he studied at the École Polytechnique in Paris, France.
Upon returning to Italy, Matteucci studied at Bologna (1832), Florence, Ravenna (1837) and Pisa. He established himself as the head of the laboratory of the Hospital of Ravenna and became a professor of physics at the local college. In 1840, by recommendation of François Arago (1786–1853), his teacher at the École Polytechnique, to the Grand-Duke ofTuscany, Matteucci accepted a post of professor of physics at the University of Pisa.
Instigated by the work of Luigi Galvani (1737–1798) on bioelectricity, Matteucci began in 1830 a series of experiments which he pursued until his death in 1865. Using a sensitive galvanometer of Leopoldo Nobili, he was able to prove that injured excitable biological tissues generated direct electrical currents, and that they could be summed up by adding elements in series, like in Alessandro Volta’s (1745-1827) electric pile.
Thus, Mateucci was able to develop what he called a "rheoscopic frog", by using the cutnerve of a frog’s leg and its attached muscle as a kind of sensitive electricity detector. His work in bioelectricity influenced directly the research developed by Emil du Bois-Reymond (1818–1896), a student of the great German biologist Johannes Peter Müller (1801–1858) in Berlin, who tried the duplicate Matteucci’s experiments and ended up discovering the nerve's action potential.
In 1844, for these studies, Matteucci was awarded with the Copley medal by the Royal Society. From 1847 he took an active part in politics, and in 1860 was chosen an Italian senator, at the same time becoming inspector-general of the Italian telegraph lines. Two years later he was appointed Minister of Education. Matteucci died in Ardenza, near Livorno, in 1868.
Victor Francis Hess (24 June 1883 – 17 December 1964) was an Austrian-American physicist, and Nobel laureate in physics, who discovered cosmic rays. Born to Vinzenz Hess and Serafine Edle von Grossbauer-Waldstätt, in Waldstein Castle, near Peggau in Styria, Austria on 24 June 1883. He attended secondary school at Graz Gymnasium from 1893 to 1901.
From 1901 to 1905 Hess was an undergraduate student at the University of Graz, and continued postgraduate studies in physics until he received his PhD there in 1910. He worked as Assistant under Stefan Meyer at the Institute for Radium Research, Viennese Academy of Sciences, from 1910 to 1920. In 1920 he married Marie Bertha Warner Breisky.
Hess took a leave of absence in 1921 and traveled to the United States, working at the US Radium Corporation, in New Jersey, and as Consulting Physicist for the US Bureau of Mines, in Washington DC. In 1923, he returned to the University of Graz, and was appointed the Ordinary Professor of Experimental Physics in 1925. The University of Innsbruck appointed him Professor, and Director Institute of Radiology, in 1931.
Hess relocated to the United States with his Jewish wife in 1938, in order to escape Nazi persecution. The same year Fordham University appointed him Professor of Physics, and he later became a naturalized United States citizen in 1944. In 1946 he wrote on the topic of the relationship between science and religion in his article "My Faith", in which he explained why he believed in God. He retired from Fordham University in 1958 and he died on 17 December 1964, in Mount Vernon, New York from Parkinson's disease.
Between 1911 and 1913, Hess undertook the work that won him the Nobel Prize in Physics in 1936. For many years, scientists had been puzzled by the levels of ionizing radiation measured in the atmosphere. The assumption at the time was that the radiation would decrease as the distance from the earth, the source of the radiation, increased.
The electroscopes previously used gave an approximate measurement of the radiation, but indicated that higher in the atmosphere the level of radiation may actually be more than that on the ground. Hess approached this mystery first by greatly increasing the precision of the measuring equipment, and then by personally taking the equipment aloft in a balloon. He systematically measured the radiation at altitudes up to 5.3 km during 1911-12. The daring flights were made both at day and during the night, at significant risk to himself.
The result of Hess's meticulous work was published in the Proceedings of the Viennese Academy of Sciences, and showed the level of radiation decreased up to an altitude of about 1 km, but above that the level increased considerably, with the radiation detected at 5 km about twice that at sea level.
His conclusion was that there was radiation penetrating the atmosphere from outer space, and his discovery was confirmed by Robert Andrews Millikan in 1925, who gave the radiation the name "cosmic rays". Hess's discovery opened the door to many new discoveries in particle and nuclear physics. In particular, both the positron and the muon were first discovered in cosmic rays by Carl David Anderson. Hess and Anderson shared the 1936 Nobel Prize in Physics.