September 22

Born near Erbil in 1211, Ibn Khallikan studied Sharia law and Arabic literature before serving as judge in several cities including Damascus and Cairo. His magnum opus, Wafayat al-A'yan, compiled detailed biographies of notable figures across the Islamic world, becoming a vital source for historians. He also wrote poetry and works on rhetoric, demonstrating a mastery of classical Arabic style. Throughout his career, he was respected for his fairness and scholarship. He died in 1282, leaving behind a legacy as one of the greatest medieval Arab historians.

Born in Wimpfen in 1547, Frischlin studied languages, law, and mathematics at the universities of Tübingen and Strasbourg. He served as a professor of poetry in Strasbourg and produced Latin tragedies, comedies, and satirical poems praised across Europe. His scientific interests led him to publish works on mathematics and astronomy that reflected the humanist spirit of the era. However, controversies over his outspoken criticism of church officials marred his career. In 1590, while fleeing legal charges, he died under mysterious circumstances, leaving behind a diverse body of work.

Jean-Étienne Guettard (1715–1786) was a French mineralogist and botanist who made foundational contributions to the study of Earth's strata and plant distribution. He produced one of the first geological maps of France, illustrating the relationship between rock types and surface formations. A member of the French Academy of Sciences, he traveled extensively to catalog minerals and flora in diverse regions. Guettard's systematic observations helped establish mineralogy as a distinct scientific discipline. He also collected botanical specimens, contributing to early plant taxonomy. His interdisciplinary approach influenced generations of naturalists and geologists.

Peter Simon Pallas (1741–1811) was a German zoologist and botanist renowned for his extensive explorations in the Russian Empire. Invited by Catherine the Great, he led journeys through Siberia and Central Asia, documenting countless species of flora and fauna. His seminal work, "Journey through Various Provinces of the Russian Empire," combined natural history with ethnographic observations. Pallas described numerous animal and plant species for the first time, contributing to taxonomy and biogeography. He also served as a professor at the University of Berlin, training the next generation of naturalists. His legacy endures in species names such as Pallas's cat and Pallas's vole.

Paolo Ruffini (1765–1822) was an Italian mathematician and philosopher who made pioneering contributions to algebra. He is famous for Ruffini's theorem, which demonstrated the insolvability of the general quintic equation by radicals. Ruffini studied medicine before devoting himself to mathematics and taught at the University of Modena. He also wrote on metaphysics and the philosophy of science, exploring the intersections between logic and mathematics. His work laid foundational ideas for later developments in group theory. Ruffini engaged in public life, supporting educational reforms during the Napoleonic era in Italy. His bold attempts to prove the quintic theorem influenced generations of mathematicians.

Michael Faraday (1791–1867) was one of the most influential experimental scientists in history. Born into a humble family, he educated himself and became assistant to Humphry Davy at the Royal Institution. Faraday discovered electromagnetic induction, the principle behind electric generators and transformers. He formulated the laws of electrolysis and introduced the concept of the electromagnetic field. His invention of the Faraday cage demonstrated his deep understanding of electric forces. Faraday delivered public lectures and wrote for general audiences, making science accessible to all. He refused honors like knighthood, focusing solely on research and discovery. His legacy continues to underpin modern physics and engineering.

Bernardino António Gomes (1806–1877) was a Portuguese physician and naturalist who advanced the study of tropical diseases. Educated at the University of Coimbra, he traveled extensively in Brazil to document the region's flora and medical conditions. Gomes researched fevers, yellow fever, and the use of native plants in treatment, publishing influential works on tropical medicine. He collected botanical specimens that enriched European herbaria and museums. As a professor of pathology in Lisbon, he mentored future generations of physicians. Gomes also contributed to natural history, classifying numerous plant species. His interdisciplinary approach bridged medicine and botany, leaving a lasting legacy in both fields.

Wilhelm Wattenbach (1819–1897) was a German historian and academic renowned for his expertise in palaeography. He studied law and history at Giessen and Leipzig before becoming professor at the University of Bonn. Wattenbach's seminal work, "Deutschlands Geschichtsquellen im Mittelalter," provided critical catalogs of medieval chronicles and documents. He was a leading figure in the Monumenta Germaniae Historica project, standardizing the editing of historical sources. Wattenbach also authored influential texts on script development and archival practices. His rigorous methodology set new standards for historical scholarship in the 19th century. His contributions continue to underpin modern medieval studies and source criticism.

Born in 1835 in Sumy, Russian Empire (now Ukraine), he studied linguistics and philosophy. Professor at Kharkiv University, he developed theories on the relationship between thought and language. His work "Language and Consciousness" argued that language shapes human perception. He introduced concepts of the linguistic sign and semantic analysis ahead of his time. Potebnja's interdisciplinary approach influenced later structuralist and semiotic scholars. He published numerous articles on Slavic philology and comparative linguistics. He died in 1891, leaving a lasting impact on the fields of linguistics and philosophy.

Ferenc Oslay was born in 1883 in the multiethnic region between Hungary and Slovenia. He devoted his career to researching and writing about the cultural and political history of Central Europe. Oslay published several monographs and articles that shed light on the diverse heritage of Slovene communities within the Austro-Hungarian Empire. His literary works combined historical scholarship with a compelling narrative style, making complex topics accessible to a wide audience. He also translated key historical texts into local languages to promote cross-cultural understanding. Oslay died in 1932, leaving behind a body of work that continues to influence regional historiography.

Frank George Woollard was born in 1883 in England and became a leading figure in the development of industrial engineering. Working for Morris Motors in the 1920s, he introduced innovative assembly flow techniques that predated the widespread adoption of mass production. Woollard's research and practical experiments on line balancing and material handling improved factory efficiency and reduced costs. He published influential papers and gave lectures on factory organization that resonated with engineers worldwide. His principles laid the groundwork for modern lean manufacturing and production systems. Woollard's contributions were recognized posthumously, and his legacy endures in production engineering practices today.

Paul Hugh Emmett earned his Ph.D. in chemistry from Caltech and co-developed the Brunauer–Emmett–Teller (BET) theory, a landmark model for measuring solid surface areas. His research advanced the understanding of catalytic processes vital to petroleum refining and industrial chemistry. During World War II, Emmett contributed his expertise to the Manhattan Project, focusing on material science challenges. After the war, he became a professor and led pioneering studies in heterogeneous catalysis, mentoring future leaders in chemical research. Emmett received numerous honors, including the National Medal of Science, for his groundbreaking contributions. He passed away in 1985, leaving an enduring impact on both academic science and practical engineering applications.