Louis Jacques Thenard, French chemist, 1824.
© Science Museum / Science & Society Picture Library
Engraved by Ambroise Tardieu after a drawing from nature. Thenard (1777-1857) was born in Louptiere, Aube in France but left for Paris as a young man to pursue a career in chemistry. In 1799 he discovered hydrogen peroxide and also produced a pigment known as Thenard's blue, an ultramarine colouring used for porcelain. In 1808 he succesfully isolated the element boron in collaboration with Joseph Louis Gay-Lusac (1778-1850). He also contributed to the studies of chlorine, iodine and potasium, and worked on esters. He wrote many scientific papers and a standard textbook, entitled 'Treatise on Chemistry', which was published to acclaim in 1813. He was elected to the Academy of Sciences and was made a baron by Charles X in 1825.