September 27

Born in 1507, Guillaume Rondelet became a prominent physician at the University of Montpellier. He conducted pioneering studies of marine life, publishing detailed observations in his seminal work ‘Libri de piscibus marinis.’ His research included anatomical dissections and precise illustrations of fish and sea creatures. Rondelet also taught notable students, including Carolus Clusius and Matthias Lobelius, influencing the next generation of naturalists. His combination of empirical observation and systematic classification helped advance early modern zoology and medicine.

Abraham Gotthelf Kästner was a German mathematician and epigrammatist known for his engaging teaching style. He served as a professor at the University of Göttingen, where he influenced future luminaries like Carl Friedrich Gauss. Kästner authored foundational textbooks on algebra and geometry that became standard references in the 18th century. His epigrams skillfully blended humor with scientific insight, making complex ideas accessible to a broader audience. He contributed essays and lectures that popularized mathematical concepts beyond the academic community. Kästner’s legacy endures in the field of mathematics education and the artful communication of scientific ideas.

Michael Denis was an Austrian lepidopterist and literary figure who bridged the worlds of science and poetry. He conducted extensive studies of butterflies and moths, contributing significant observations to the field of entomology. Denis published descriptive works on Lepidoptera that advanced the classification and understanding of these insects. Beyond science, he was a prolific poet and author, composing epigrams, essays, and literary critiques in German. He co-founded the Viennese literary society ‘Meistersingers’ and influenced the cultural life of 18th-century Austria. Denis’s diverse talents exemplify the Enlightenment ideal of a polymath engaged in both scientific inquiry and the arts.

Hermann Kolbe was a leading 19th-century German chemist recognized for his contributions to organic chemistry. He developed the Kolbe electrolysis method for synthesizing hydrocarbons from carboxylic acids. Kolbe’s research helped establish the foundations of structural theory in chemistry and organic synthesis. He held professorships at the University of Marburg and the University of Leipzig, influencing a generation of chemists. His work demonstrated the importance of carbon chain formation and reaction mechanisms in organic compounds. Kolbe’s legacy endures in modern chemical practices and the continued application of his electrolysis techniques.

William Babcock Hazen (1830–1887) served as a Union Army general during the American Civil War, distinguishing himself at battles such as Fort Donelson and Vicksburg. After the war, he became the U.S. Army Chief Signal Officer and played a pivotal role in developing early weather forecasting techniques. Hazen oversaw the expansion of the Signal Corps into a national meteorological service. He introduced systematic weather observations and forecasting that laid the foundation for modern meteorology. Hazen also contributed to advancements in telegraphy and military communications. His work had a lasting impact on both military operations and civilian weather services. He is remembered as a forward-thinking innovator in military science.

Alfred Thayer Mahan (1840–1914) was a United States Navy captain and historian whose landmark book, The Influence of Sea Power upon History, revolutionized naval strategy and political thought. His analysis of maritime dominance influenced naval policies in the United States, Britain, Germany, and beyond. Mahan served in the Civil War, commanding gunboats along the Mississippi River before joining the Naval War College faculty. He later became president of the college and taught future strategists. His writings underscored the importance of naval supremacy in global power. Mahan’s theories helped spur a naval arms race in the late 19th and early 20th centuries. Today, he is regarded as the father of sea power studies.

Alphonse François Renard (1842–1903) was a Belgian geologist and petrographer whose pioneering research advanced the understanding of rock formation and mineral textures. He conducted extensive fieldwork in Europe, studying crystalline schists and metamorphic processes. Renard introduced microscopic techniques to petrography, allowing scientists to examine thin rock sections and identify mineral compositions. His collaborative work with British geologists helped establish international standards in petrographic methods. Renard’s publications influenced the development of the Geological Survey of Belgium. He was also a professor at the University of Liège, mentoring a generation of geologists. His contributions laid the groundwork for modern igneous petrology.

Gaston Tarry (1843–1913) was a French mathematician celebrated for his work in number theory and combinatorial design. He is best known for the Prouhet–Tarry–Escott problem, which investigates equal sum partitions of powers. Tarry also studied Latin squares and made contributions to finite geometry. He served as a professor at the University of Toulouse, where he influenced students and colleagues with his elegant proofs. His research bridged pure and applied mathematics, finding applications in statistical design and cryptography. Tarry’s insights continue to inform mathematical theory over a century later. He was elected to the French Academy of Sciences in recognition of his achievements.

An early pioneer of functional analysis, Hans Hahn formulated the Hahn-Banach theorem. His research extended to set theory, topology, and the foundations of mathematics. As a professor at the University of Vienna, he mentored students like Kurt Gödel. He co-founded the Vienna Mathematical Society, fostering collaboration among scholars. His blend of philosophical inquiry and mathematical rigor influenced 20th-century logic.

Sergei Varshavsky devoted his life to the collection and study of Western European art. A prolific author, he published numerous books and articles on Renaissance and Baroque masters. His private collection included rare works by Titian, Rubens, and Rembrandt, which he often loaned to museums. Varshavsky's scholarship bridged the gap between curatorship and academia, making art history accessible to a broader audience. He served in cultural institutions to preserve Russia's artistic heritage during turbulent times. His contributions significantly influenced the appreciation and preservation of European art in the Soviet Union. He passed away in 1980, leaving a legacy celebrated by art historians and collectors alike.

Albert Ellis was born in 1913 in Pittsburgh, Pennsylvania and became one of the most influential psychologists of the twentieth century. He founded Rational Emotive Behavior Therapy (REBT), which emphasizes the role of irrational beliefs in emotional distress. Ellis studied at Columbia University and went on to lecture and practice in New York City. He authored more than 80 books and 1,000 articles on psychotherapy, personality, and emotional well-being. Ellis's direct and confrontational style challenged traditional psychoanalytic approaches and paved the way for modern cognitive therapies. Throughout his career, he founded the Albert Ellis Institute to train therapists in REBT. His work has had a lasting impact on the treatment of anxiety, depression, and other mental health issues. Ellis passed away in 2007 at the age of 93, leaving a profound legacy in clinical psychology.

S. Yizhar was born Yizhar Smilansky in 1916 in Nahalal, Ottoman Palestine. He served in the 1948 Arab–Israeli War and later became a professor of literature and an influential voice in Israeli academia. Yizhar was elected to the Knesset as a member of Mapai and served multiple terms, focusing on education and cultural affairs. He published numerous essays and scholarly works exploring Hebrew literature and nationalism. Yizhar's contributions helped shape early Israeli educational policy and fostered an appreciation of literary heritage. In addition to his political career, he continued to teach and mentor students, leaving a lasting impact on generations of Israeli intellectuals. He passed away in 2006, remembered for bridging the worlds of scholarship and public service.