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<b>August 14</b><br /><br /><font color="orange">People</font><br /><br /><b>Arthur Jeffrey Dempster</b><br /><br /><i>Born 14 Aug 1886; died 11 Mar 1950. <br /><br />Canadian-American physicist who in 1918 built the first mass spectrometer (based on the invention of Francis W. Aston) and discovered isotope uranium-235 (1935). The mass spectrometer is an instrument that uses electric and magnetic fields to separate and measure a sample's atoms according to their mass and relative quantity. In 1935, he discovered that naturally occurring uranium, though mostly uranium-238, contained 0.7% U-235 (later used as the primary fuel in atomic bombs and reactors after Niels Bohr predicted it could be used to produce a chain reaction releasing huge amounts of nuclear fission energy). During WW II, Dempster worked with the secret Manhattan Project that developed the world's first nuclear weapons. </i><br /><br /><b>Jean-Gaston Darboux</b><br /><br /><i>Born 14 Aug 1842 <br /><br />French mathematician whose work on partial differential equations introduced a new method of integration (the Darboux integral) and contributed to infinitesimal geometry. He wrote a paper in 1870 on differential equations of the second order in which he presented the Darboux integral. In 1873, Darboux wrote a paper on cyclides and between 1887-96 he produced four volumes on infinitesimal geometry, including a discussion of one surface rolling on another surface. In particular he studied the geometrical configuration generated by points and lines which are fixed on the rolling surface. He also studied the problem of finding the shortest path between two points on a surface. </i><br /><br /><b>John Jeremiah Bigbsy</b><br /><br /><i>Born 14 Aug 1792; died 10 Feb 1881 <br /><br />English physician and geologist whose extensive geologic studies of Canada and New York revealed much of the structure of the underlying rock strata and uncovered many new species of prehistoric life. </i><br /><br /><b>Hans Christian Oerst</b> <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis: </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>