The ‘chemical revolution’ of the late eighteenth century had the effect not only of expanding the field of scientific endeavour but of focussing the attention of bright young men of the time on that particular branch of science.

Within three years of the year of birth of Gay-Lussac (1778) there were born four other men who were each to establish a considerable reputation for themselves in chemical science: Amedeo Avogadro (1776–1856), Jöns Jacob Berzelius (1779–1848), Humphry Davy (1778–1829) and Louis Jacques Thenard (1777–1857). All came to have a great respect for Gay-Lussac although most of them had little direct contact with him. Most remote was Avogadro, on the far side of the Alps condemned to obscurity and isolation from the main centres of scientific research and publication. Yet Avogadro's great claim to fame (‘Avogadro's hypothesis’) is a direct inference from the Frenchman's law of combining volumes of gases, a connection fully and explicitly acknowledged by the Italian. The Swede, Berzelius, too was to derive inspiration from the publications of Gay-Lussac, whom he was to meet during his stay in Paris in 1818–19.