Abstract :
In several respects Tyndall is the founder of applied aerosol science. His research, demonstrations, and lectures profoundly influenced Zsigmondy and the development of the ultramicroscope. This is the tool used by Perrin to experimentally test the theories of Brownian motion of Smoluchowski and Einstein. His speculation on the cause of the color of the sky directly inspired Rayleigh to develop a mathematical theory for light scattering for small particles. This then led to the development of scattering theory by Mie and Debije for micron size particles. Brownian motion and the size-wave length dependence of light, cornerstones of 20th century aerosol science, were direct extensions of Tyndallʹs study.
The historical role of Tyndall in the use of aerosol to disestablish heterogenesis, in the design of respirators, and in monitoring environmental contamination resonate to the present day. But to emphasize only his work on dark field illumination and the scattering of light by small particles, slights his critical study on radiant heat. The appropriate treatment of absorption and emission of radiant heat where both particles and gasses are present remain an open question to the present.
