July 27

Born in 1593, Salomo Glassius studied theology and became a professor at the University of Jena. He authored the influential 'Philologia Sacra', which shaped Protestant biblical interpretation. His work combined philology with theology, advancing critical methods in scriptural studies. Glassius served as court preacher in Weimar and contributed to spiritual discourse during the Thirty Years' War. He left a lasting impact on hermeneutics and German Protestant scholarship before his death in 1656.

Born in 1698 in Saint-Malo, France, Maupertuis excelled in mathematics and natural philosophy. He solved key problems in the calculus of variations and introduced the principle of least action. In 1736, he led the Lapland expedition to measure a degree of meridian, confirming Earth's oblate shape. As president of the Berlin Academy, he corresponded with Euler and Leibniz, advancing Enlightenment science. His writings bridged mathematics and metaphysics, influencing later developments in physics and philosophy. Maupertuis died in 1759, leaving a legacy as a pioneer of scientific exploration and thought.

Born in 1766 in Eaglesfield, England, Dalton began his scientific career as a schoolteacher. He conducted groundbreaking experiments on gases, leading to Dalton's law of partial pressures. In his 1808 work 'New System of Chemical Philosophy', he proposed that matter is composed of indivisible atoms. Dalton's assignments of atomic weights revolutionized chemistry and laid groundwork for stoichiometry. He made important meteorological observations and studied color blindness, later termed 'Daltonism'. Elected to the Royal Society in 1822, Dalton remained active in research until his death in 1844.

Emil Theodor Kocher (1841–1917) was a Swiss physician whose innovations transformed modern surgery. He developed safer techniques for thyroidectomy, drastically reducing patient mortality. In 1909, Kocher became the first Swiss scientist to receive the Nobel Prize in Physiology or Medicine. As a professor at the University of Bern, he trained generations of surgeons in antiseptic methods. His research also advanced neurosurgery and the understanding of aseptic technique. Kocher's legacy endures in surgical best practices and medical education worldwide.

Auguste Forel (1848–1931) was a Swiss scientist whose interdisciplinary work spanned neuroscience and psychiatry. He conducted groundbreaking studies on glial cells and the organization of the nervous system. Forel introduced antiseptic methods and humane treatment in psychiatric hospitals. Beyond medicine, he advocated for social reforms, including temperance and direct democracy. His prolific writings influenced both neurological research and mental health care policies. Forel's contributions continue to inform contemporary neuropsychiatric practices.

Paul Kogerman was born in 1891 in what was then part of the Russian Empire and became a leading figure in oil shale research. He earned his doctorate in chemistry at the University of Tartu and conducted groundbreaking studies on the composition and industrial potential of Estonian oil shale. Kogerman published influential papers that laid the foundation for modern oil shale processing techniques. In addition to his scientific career, he served as the 22nd Minister of Education for Estonia, advocating for the advancement of scientific education. He promoted the establishment of research institutes and collaborations with European universities. After Soviet occupation, Kogerman continued his work in exile, preserving the scientific heritage of his homeland. He died on July 27, 1951, leaving a dual legacy in both chemistry and public service.

Julie Vinter Hansen was born in Copenhagen in 1890 and earned her doctorate in astronomy at the University of Copenhagen. She worked at the Copenhagen Observatory under director Elis Strömgren, focusing on precise calculations of planetary and lunar orbits. Hansen played a key role in compiling and updating star catalogs, improving the accuracy of positional astronomy. In 1943, she became one of the first women to serve as a professor at the University of Aarhus, promoting astronomy education across Scandinavia. She published numerous papers on celestial mechanics and directed observational programs that contributed to international ephemeris services. Hansen was also active in scientific societies, advocating for women in science. She passed away in 1960, leaving a legacy of meticulous research and mentorship.

Garrett Morgan (1877–1963) was an African American inventor and business leader whose innovations had a profound public impact. Frustrated by industrial accidents, he developed a safety hood in 1914 that evolved into the modern gas mask and remains a standard in respiratory protection. In 1923, Morgan patented a three-position traffic signal that added a 'warning' phase, improving road safety worldwide. He founded the Garrett Morgan Manufacturing Company to produce and market his inventions. Morgan overcame racial barriers of his time to secure patents and run a successful business. His contributions saved countless lives in mines, battlefields, and city streets. Morgan's ingenuity and perseverance paved the way for future inventors and civil rights pioneers.

Born in Budapest in 1890, Elizabeth Rona earned her doctorate in chemistry studying under George de Hevesy. She conducted groundbreaking work on radioactive isotopes and developed methods for separating uranium isotopes. During the 1930s, Rona worked at the Kaiser Wilhelm Institute before emigrating to the United States in 1938 to escape rising tensions in Europe. At Columbia University, she joined the team that produced the world's first sample of thorium-series radioisotopes. Her research contributed to early advances in nuclear medicine and reactor technology. Facing challenges as a woman in a male-dominated field, Rona became a respected mentor to younger chemists. Elizabeth Rona died on July 27, 1981, remembered for her pioneering contributions to nuclear chemistry.

Aleksandr Danilovich Aleksandrov was a Soviet mathematician and physicist renowned for his work in geometry and the theory of relativity. He formulated foundational results in convex geometry and differential equations that remain influential. Aleksandrov served as director of the Steklov Institute of Mathematics, guiding generations of scientists. Outside academia, he was an avid mountaineer, leading expeditions in the Caucasus mountains. He authored numerous textbooks that became standard references in the field. Aleksandrov received prestigious awards such as the Lenin Prize for his outstanding contributions to science. His interdisciplinary approach bridged abstract mathematics with applied physics. His legacy endures in the global mathematical community.

Maryann Mahaffey (1925–2006) was a dedicated academic and public servant. She served on the Detroit City Council for over three decades, championing education and consumer protection. Mahaffey was instrumental in advancing public health initiatives, including early smoking restrictions. Her leadership and advocacy helped shape policies that improved community welfare in Detroit. Her legacy remains that of a pioneering woman in American local politics.

A. P. J. Abdul Kalam was an Indian aerospace scientist and engineer who played a pivotal role in India's missile and space programs. Known as the 'Missile Man of India', he directed projects that advanced the nation's defense and technology capabilities. Later, Kalam served as the 11th President of India from 2002 to 2007, earning widespread admiration for his humility, vision, and encouragement of youth. An inspiring educator and author, he wrote several books, including his autobiography 'Wings of Fire'. His legacy endures in India's scientific community and among generations inspired by his leadership. Kalam passed away in 2015, continuing to be celebrated as a national icon.