He worked in the fields of spectroscopy, atmospheric physics and meteorology. In the field of spectroscopy he found the shift of spectral lines under pressure. In atmospheric physics he found a very good model for the stratosphere in 1909. He wrote numerous books, including a textbook titled Physics of the Air, first published in 1920 and considered a standard work of the time,[2] though it was last published in 1940.[citation needed] He also held some teaching positions at universities. He concluded that the 1815 eruption of Mount Tambora was responsible for the subsequent cooling known as the Year Without a Summer.[3]
[1] Humphreys, W. J. “Volcanic Dust as a Factor in the Production of Climatic Changes.” Journal of the Washington Academy of Sciences 3, no. 13 (1913): 365–71.
^Humphreys, W. J. "The effect of surface drag on surface winds". In: Proceedings of the International Congress of Mathematicians in Toronto, August 11–16. 1924. Vol. 2. pp. 297–304.