Claude Louis Berthollet

Claude Louis Berthollet arrived in Paris from Savoy and swiftly became a central figure in the explosive rise of modern chemistry. A colleague of Lavoisier, he survived the political turmoil of the French Revolution to become a scientific advisor to Napoleon, even joining his expedition to Egypt. Berthollet's mind was both theoretical and intensely practical. He challenged the idea that chemical affinities were fixed, proposing that reactions could run in reverse—a foundational concept for chemical equilibrium. In his laboratory at Arcueil, he made a discovery that would whiten the world: he demonstrated that chlorine gas could bleach textiles, and later developed a practical bleaching solution, sodium hypochlorite, revolutionizing the linen and cotton industries and paving the way for modern laundry bleach.