Samuel Alfred Mitchell
Samuel Alfred Mitchell was born in Kingston, Ontario on April 29, 1874. This son of John Cook and Sarah Chown Mitchell was the sixth of ten children to grow up in the Mitchell home. At age twelve, undoubtedly to get away from his many siblings, he went off to Kingston Collegiate Institute. From there, he went on to Queen's University where he received his Masters of Arts in mathematics in 1894. While at Queen's University, he was introduced to Reverend James Williamson, known as Uncle Billy, who at eighty years of age found it pleasant to delegate the care of the astronomical instruments to Mitchell which is how he acquired knowledge of the techniques of an astronomical observatory.
Upon encouragement from his math professor, Nathan F. Dupuis, he left in 1895 for The Johns Hopkins University to study math under Simon Newcomb, only to find Newcomb retired. Thomas Craig was the new head of mathematics and Mitchell also began study under Charles Lane Poor, the head of astronomy. Poor was an excellent teacher and Mitchell was inclined to follow astronomy from that point on. Mitchell was awarded an astronomy assistantship for his second year at JHU and continued until he received his PhD in 1898 with his thesis published in the Astrophysical Journal, which included a discussion of the amount of astigmatism of concave grating. While at Hopkins, his astronomy duties consisted of caring for the transit instrument and the clocks in the little observatory behind the physics laboratory, and the 9.5-inch refractor in the dome of the laboratory roof.
Following receipt of his doctoral degree, Mitchell set out for the brand new Yerkes Observatory in Wisconsin where he began work as a research student in 1898. Though he enjoyed his work at Yerkes, he was enticed to move away and became an instructor in astronomy at Columbia University in June 1899. The following December he married the daughter of Professor E. T. Dumble who was then the State Geologist of Texas. Over the fourteen years he was at Columbia, Mitchell taught undergraduate courses in descriptive astronomy both at Columbia and later for girls from Barnard College, a year long course in geodesy for third year students, which continued into a first semester fourth year course, and a six week summer camp for civil engineers.
he took what would be for him the first of ten eclipse expeditions. The
May 28, 1900 eclipse took him to Griffin, Georgia with the United States
Naval Observatory. Mitchell became a world-renowned authority on
solar eclipses through his numerous expeditions, including trips to:
Sumatra in the Dutch West Indies (1901), Spain (1905), Oregon (1918),
San Diego (1923), Connecticut (1925), Norway (1927), "Tin-Can Island" in
the South Pacific Ocean (1930) and Magog in Canada (1932), with one
final expedition taking place in 1937. These ten expeditions allowed him
to write Eclipses of the Sun, summarizing his work on solar flash
spectra, first published in 1923 and produced through five editions.