Reported in a 10-page biography of Tyndall by Arthur Whitmore Smith, a professor of physics, writing in an American scientific monthly in 1920; available online.
Smith, Glenn S. (2005). "Human color vision and the unsaturated blue color of the daytime sky". American Journal of Physics. 73 (7): 590–97. Bibcode:2005AmJPh..73..590S. doi:10.1119/1.1858479.
Smith, Glenn S. (2005). "Human color vision and the unsaturated blue color of the daytime sky". American Journal of Physics. 73 (7): 590–97. Bibcode:2005AmJPh..73..590S. doi:10.1119/1.1858479.
nih.gov
pubmed.ncbi.nlm.nih.gov
Mappes, Timo; Jahr, Norbert; Csaki, Andrea; Vogler, Nadine; Popp, Jürgen; Fritzsche, Wolfgang (2012). "The Invention of Immersion Ultramicroscopy in 1912-The Birth of Nanotechnology?". Angewandte Chemie International Edition. 51 (45): 11208–11212. doi:10.1002/anie.201204688. PMID23065955.