It should first be noted that Jean-Baptiste Say, when training as a young merchant, spent two years with his younger brother Horace at a merchant’s in Croydon. In 1786, he went to Great Britain to be trained in the practice of English business affairs. This, in the midst of the period of development of manufacturing in Great Britain, when the introduction of mechanical looms gave a great boost to industrial activity as a whole. It is clear that this first experience in an industrial environment, in full-swing and lasting two years, deeply influenced the young Say, who was endowed with a curious and observant mind. The other element that makes Say a competent expert to analyze the economic situation in England and identify important points and lessons for France lies in his experience as an entrepreneur in the creation of the spinning company in Auchy in 1805. JEL Codes : B12