Gilbert Lewis

Gilbert Newton Lewis was born on October 23, 1875 in Weymouth, Massachusetts. His father, Francis Lewis, was a lawyer. When he was nine his parents moved to Lincoln, Nebraska. Lewis had no formal schooling until he was admitted to a preparatory school for the University of Nebraska at the age of 13. He attended the University of Nebraska for two years, then in 1893 he went to Harvard College where he graduated in 1896. After a year of teaching at Philips Academy Andover outside of Boston he returned to Harvard where he earned his MA in 1898 and his PhD in 1899 with a dissertation on electrochemical potentials. He remained at Harvard for on more year as an instructor then went on a traveling fellowship where he visited Wilhelm Ostwald in Leipzig and Walther Nernst in Gottingen. When he returned he spent three more years at Harvard before moving the the Philippines where he was superintendent of weights and measures and chemist at the Bureau of Science.

He returned to the United States in 1905 to a faculty position at the Massachusetts Institute of Technology, where he was appointed assistant professor in 1907, associate professor in 1908, and full professor in 1911. In 1912 he left M.I.T. for the University of California at Berkeley where he was dean of chemistry and a professor of physical chemistry. His time in California was interrupted by First World War when Lewis served as a major in the gas service and chemical warfare service.

His first research interest was thermodynamics. He introduced the idea of activity, or the effective concentration of a chemical species in solution. Lewis is best remembered for his valence theory and the eponymous dot structures. Lewis pictured atoms as cubes with the electrons at the corners. We now know that atoms are spherical and their electrons are spread out in orbitals. Lewis also wrote papers on relativity and defined acids and bases as electron acceptors and electron donators respectively. Lewis was the first to produce deuterium oxide (heavy water) using Ernest Lawrence's cyclotron in 1933.

Honors won by Lewis include election in to the National Academy of Science in 1913. Because of his disagreements with Walther Nernst he was never awarded the Nobel Prize although he was nominated 30 times. He was awarded numerous honorary doctorates and membership in Royal Society, the Chemical Society of London and the Indian, Swedish, and Danish Academies of Science.

On March 23, 1946 Lewis died in a laboratory accident involving hydrogen cyanide which some believed was suicide.


References:

Carey, Charles W.; "Lewis, Gilbert N." in American Scientists; Infobase Publishing; 2006

Hildebrand, Joel H.; "Gilbert Newton Lewis; 1875-1946"; National Academy Press; 1958

Gilbert N. Lewis Wikipedia Entry

Cato Maximilian Guldberg

Cato Maximilian Guldberg was born on August 11, 1836 in Christiania (now Oslo) , Norway. He was educated at the University of Christiania. Starting in 1860 he taught mathematics at the Royal Military School. Later he became a professor of applied mathematics at the University of Christiana.

In 1863, working in collaboration with his brother-in-law Peter Waage (with whom he is pictured above, Guldberg is on the left) he formulated the law of mass action. This is a chemical law that says that the rate of any chemical reaction is proportional to the concentration of the reacting chemical(s). So for the chemical reaction A + B -> C, the rate of the reaction will be a constant (k) times the concentrations of A and B, such that rate = k[A][B], where [A] and [B] are the concentrations of A and B. Guldberg and Waage also investigated the effects of temperature on chemical reaction rates. Because Guldberg and Waage published in Norwegian the law of mass action when first published was largely ignored. When it was republished in French it still drew little attention until it was experimentally demonstrated by William Esson and Vernon Harcourt working at Oxford University.

Starting in 1870 Gulberg investigated how a dissolved substance affects the freezing point and vapor pressure of a pure liquid. In 1890 he formulated Guldberg's law which says that the boiling point of a liquid is two thirds the temperature of its critical temperature, the temperature at which a gas cannot be liquefied by increased pressure alone.

Gulberg died on January, 14, 1902 in his native city, which had respelled it's name to Kristiania.


References:

Daintith, John; "Guldberg, Cato Maximilian (1836-1902)" in Biographical Encyclopedia of Scientists, Third Edition; CRC Press; 2010

Tilden, Sir William Augustus; "Cato Maximilian Guldberg" in The Progress of Scientific Chemistry of Our Times; Longmans, Green; 1913

Cato Maximilian Guldberg Wikipedia Entry

William Thompson, Baron Kelvin

William Thompson was born on June 26, 1824 in Belfast, Ireland, of Scottish-Irish descent. His father, James Thompson was at the time a mathematics professor at the Royal Belfast Academical Institution. His mother, Margaret Gardner, died in 1830 and in 1832 his father took his six children with him to Glasgow, Scotland, where he had been elected chair of mathematics at the University of Glasgow, his alma mater.

William, and his older brother James received their early education at home, from their father. He entered the University of Glasgow in 1834 at the age of ten. At 12 he won a prize for translating Lucian of Samosata's Dialogs of the Gods from Latin into English. His first scientific paper was published in 1841 and in that year he entered St. Peter's College, Cambridge to read for the mathematical tripos. During his time at Cambridge he rowed for his college and remained involved in nautical pursuits throughout his life. He graduated in 1845, second wrangler (the university examiner commented that the Senior Wrangler "was not fit to cut pencils for Thompson") and winning first place in the Smith's Prize competition. He was elected fellow, shortly thereafter.

At the time experimental physics was not taking place at Cambridge, so after graduation he took his fellowship to Paris, and he worked in the laboratory of Henri Regnault for a year, where he determined data on a number of physical constants. In 1846 the chair of natural philosophy at Glasgow University became vacant and Thompson was elected. He remained in the position for fifty-three years until his retirement in 1899, despite many invitations to leave and go elsewhere. He was an inexhaustible worker, producing almost six hundred papers, seventy patents, as well as a number of books during his tenure.

Thompson is most famous for his work on an absolute zero temperature, a temperature at which entropy is reduced to its lowest possible value. The Kelvin temperature scale, named after Thompson, has its zero at -273.15 degrees Celsius or -459.67 degrees Fahrenheit. At this temperature nearly all molecular motion stops and pure substance form perfect crystals. It is not possible to reach absolute zero artificially, but there are techniques to get within a billionth of a degree using cooling lasers.

Thompson served as the electrical engineer during the laying of the first successful Transatlantic Telegraph Cable and was knighted for his services. He was elected to the Royal Society in 1851 and won the Copley Medal in 1883. His title, Barron Kelvin, bestowed on him in 1892, origninated from the River Kelvin which runs through the grounds of the University of Glasgow and he is the first scientist who served in the House of Lords.

He died on December 17, 1907.

References:

Fitzgerald, George Francis;Lord Kelvin: Professor of Natural Philosophy in the University of Glasgow 1846-1899 with an Essay on His Scientific Work;J. MacLehose; 1899

McKie, Dr. Douglas;"William Thompson: Lord Kelvin (1824-1907)";New Scientist(1957)3:11-13

William Thompson, 1st Barron Kelvin Wikipedia Entry

Julius Robert von Mayer

Julius Robert von Mayer, born on November 25, 1814, was one of the pioneers of thermodynamics for enunciating one of the first formulations of the First Law: "Energy can not be created or destroyed".

Mayer grew up in Heilbronn, in southern Rhineland, the son of a pharmacist he studied medicine at the University of Tubingen. After attaining his doctorate, he signed on as ship's physician on Dutch three-masted sailing ship on a trip to Jakarta.

This trip spurred his interest in the physical sciences. His observation that wind swept waves were warmer than calm seas led him to wonder about the physical phenomenon of warmth. Also while in the tropics he observed that the blood of his patients was redder than it would be in northern climes. While operating on a patient he saw the redder blood and feared he had severed an artery. Only after being reassured by local physicians did he realize that this was normal. In the tropics not as much oxygen is required to warm the body and thus the blood traveling back to the heart is more oxygenated and redder than venous blood in cooler climes where more oxygen is required to maintain temperature. This led Mayer to believe that oxidation was the primary source of energy in living things.

Upon returning to Germany Mayer wrote a paper outlining his observations, however the paper contained no experimental results and was rejected. Unable to get clarification on why his paper was rejected Mayer (relying on the experimental work of others) wrote another paper in which he proposed that mechanical energy and heat energy were equivalent, specifically that the dropping of a weight from 365meters was equivalent to warming an equivalent mass of water from 0 to 1 degree Celsius. The current accepted value for this standard is 418.4meters.

At the time Mayer's work was largely ignored and credit for the discovery of the equivalence of mechanical and heat energy was initially given to James Joule (for whom the unit of energy is named). In 1848 when Mayer tried to assert his precedence, Joule admitted Mayer's precedence but claimed credit for the experimental demonstration of the theory. This controversy, plus the loss of two of his children, caused Mayer to attempt suicide in 1850. Mayer's work led Herman von Helmholtz to formulate the general principal of conservation of energy in 1848.

For his work in describing the principal of the conservation of energy Julius Robert von Mayer is the Dead Scientist of the Week for the week of November 22-28, 2009.

References:

Julius Robert von Mayer Wikipedia Entry

Mechanical equivalent of heat Wikipedia Entry

Cobb, Kathy; Goldwhite, Harold; Creations of Fire: Chemistry's Lively History from Alchemy to the Atomic Age; Basic Books, 2002