 France was experiencing a butter shortage, and Napoleon III offered a prize for producing a butter substitute.Mège-Mouriès experimented with what was believed to be a new fatty acid discovered by Michel Eugene Chevreul, acide margarique or margaric acid.By 1867, Mège-Mouriès was working at la Ferme Impériale de la Faisanderie, Napoleon III's private farm in Vincennes near Paris.