Spiral

Building spiral turbines c. 1930

Retronaut | Source: German Federal Archive

Vintage Photo

R101 was one of a pair of British rigid airships completed in 1929 as part of a British government programme to develop civil airships capable of service on long-distance routes within the British Empire. It was designed and built by an Air Ministry-appointed team and was effectively in competition with the government-funded but privately-designed and built R100. When built it was the world's largest flying craft,and it was not surpassed until the Hindenburg flew five years later. After some trial flights, and subsequent modifications to increase lifting capacity which included lengthening the airship by 46 ft (14 m), it crashed on 5 October 1930 in France during its maiden overseas voyage, killing 48 of the 54 people on board.

Source: wikipedia | PD-BRITISHGOV. | Wikipeterproject at en.wikipedia

Marie Daly

Marie Maynard Daly, born in Queens, New York to Helen and Ivan Daly, was the first black woman to earn a Ph.D. in Chemistry.

(1921-2003)

Source: blackpast | Ray Spangenburg and Kit Moser. “Roger Arliner Young,” in African Americans in Science, Math, and Invention (New York: Facts on File, 2003); James H. Kessler. “Marie Maynard Daly,” in Distinguished African American Scientists of the Twentieth Century (Phoenix: Oryx Press, 1996); https://webfiles.uci.edu/mcbrown/display/daly.html