Six Lectures on Light / Delivered In The United States In 1872-1873

The lectures present a systematic, experimentally grounded account of optical phenomena, beginning with basic laws of propagation, reflection, and refraction, and surveying measurements of light's speed. They trace the development of theoretical ideas from emission views to the wave description, illustrating interference, diffraction, and the role of the luminiferous ether. Polarization and double refraction are examined through crystalline behavior and laboratory demonstrations, including strain and circular effects. The spectrum and invisible radiation are treated together, showing relations between emission and absorption, the identification of spectral lines, and practical uses of spectroscopic analysis. A concluding synthesis connects theory, experiment, and applications across visible and radiant heat.