During the late eighteenth and early nineteenth centuries, the most avidly debated topic among scientists worldwide was the nature of light: was it a beam of flowing particles, a theory which had become generally accepted, or could there be truth in the wave theories recently popularized by Thomas Young and Augustin-Jean Fresnel? Each side fought bitterly and tenaciously to prove or disprove these theories. From their efforts grew much of our modern understanding of the behavior of light, not the least of which is Jean-Baptiste Biot's study of polarization.

Biot was born in Paris in 1774. His father, who had risen from peasant stock to become a treasury official, enrolled him in private mathematics lessons, with the intention of steering him toward a career in commerce. Biot circumvented his father's plans by serving a brief stint in the army before enrolling at the École des Ponts et Chauss...