Ancient Chinese scientists and engineers made significant scientific innovations, findings and technological advances across various scientific disciplines including the natural sciences, engineering, medicine, military technology, mathematics, geology and astronomy.

Among the earliest inventions were the abacus, the sundial, and the Kongming lantern. The Four Great Inventions,the compass, gunpowder, papermaking, and printing – were among the most important technological advances, only known to Europe by the end of the Middle Ages 1000 years later. The Tang dynasty (AD 618–906) in particular was a time of great innovation. A good deal of exchange occurred between Western and Chinese discoveries up to the Qing dynasty. (Full article...)

An allegorical anatomy engraving from Andreas Vesalius's De humani corporis fabrica (1543), imparting a moral lesson on the consequences of evil and a physical lesson on the internal structure of the body.

...that the travel narrative The Malay Archipelago, by biologist Alfred Russel Wallace, was used by the novelist Joseph Conrad as a source for his novel Lord Jim?

...that the seventeenth century philosophers René Descartes, Baruch Spinoza, and Gottfried Leibniz, along with their Empiricist contemporary Thomas Hobbes all formulated definitions of conatus, an innate inclination of a thing to continue to exist and enhance itself?

...that according to the controversial Hockney-Falco thesis, the rise of realism in Renaissance art, such as Jan Van Eyck's Arnolfini Portrait (pictured), was largely due to the use of curved mirrors and other optical aids?

Barbara McClintock (June 16, 1902 – September 2, 1992) was an American scientist and cytogeneticist who was awarded the 1983 Nobel Prize in Physiology or Medicine. McClintock received her PhD in botany from Cornell University in 1927. There she started her career as the leader of the development of maize cytogenetics, the focus of her research for the rest of her life. From the late 1920s, McClintock studied chromosomes and how they change during reproduction in maize. She developed the technique for visualizing maize chromosomes and used microscopic analysis to demonstrate many fundamental genetic ideas. One of those ideas was the notion of genetic recombination by crossing-over during meiosis—a mechanism by which chromosomes exchange information. She produced the first genetic map for maize, linking regions of the chromosome to physical traits. She demonstrated the role of the telomere and centromere, regions of the chromosome that are important in the conservation of genetic information. She was recognized as among the best in the field, awarded prestigious fellowships, and elected a member of the National Academy of Sciences in 1944.

During the 1940s and 1950s, McClintock discovered transposons and used it to demonstrate that genes are responsible for turning physical characteristics on and off. She developed theories to explain the suppression and expression of genetic information from one generation of maize plants to the next. Due to skepticism of her research and its implications, she stopped publishing her data in 1953. (Full article...)

April 24:

• 1620 - Birth of John Graunt, English statistician and founder of the science of demography (d. 1674)

• 1656 - Death of Thomas Fincke, Danish mathematician and physicist (b. 1561)

• 1899 - Birth of Oscar Zariski, Russian-born mathematician (d. 1986)

• 1916 - Ernest Shackleton and five men of the Imperial Trans-Antarctic Expedition launch a lifeboat from uninhabited Elephant Island in the Southern Ocean to organise a rescue for ice-trapped ship Endurance

• 1947 - Birth of Roger D. Kornberg, American chemist, Nobel-prized

• 1960 - Death of Max von Laue, German physicist, Nobel Prize laureate (b. 1879)

• 1964 - Death of Gerhard Domagk, German bacteriologist, recipient of the Nobel Prize in Physiology or Medicine (declined) (b. 1895)

• 1990 - STS-31: The Hubble Space Telescope is launched by the Space Shuttle Discovery