July 15 – F. W. Aston shows that the molar mass of chlorine (35.45) is a weighted average of the almost integral masses for the two isotopes35Cl and 37Cl.[4]
History of science and technology
September 10 – Newcomen Society founded in the United Kingdom for the study of the history of engineering and technology.[5]
Medicine
October 31 – Dr. Frederick Banting of Ontario first records his insight on how to isolate insulin for the treatment of diabetes;[citation needed] working with Charles Best, the first successful human trial of insulin will occur 15 months later.
Milutin Milanković proposes that long term climatic cycles may be due to changes in the eccentricity of the Earth's orbit and changes in the Earth's obliquity ("Milankovitch cycles").[7]
Russell, Ben (2023). "A curator at the height of his power: H. W. Dickinson... and the Newcomen Society, 1919–1930". International Journal for the History of Engineering and Technology. 93: 1–15.