The soft-paste porcelain produced at Vincennes between 1740 and 1750 may be distinguished from other porcelain manufactured in France over the same period by its exceptional whiteness and transparency, the result of a secret way of preparing the body. In France at that time, potters only knew how to make non-China clay porcelain using a pulverized frit and a plastic element known as body , consisting of calcareous marl and chalk. The details of the composition were guarded by each individual factory, but at Vincennes it was the person who supplied the body, Francois Gravant, who possessed the secret. In 1748, Gravant had sold the secret to the factory manager, following whose death in 1751 Jean Hellot was charged, on behalf of the king, with the collection of all the manufacturing secrets and processes. From 1751 to 1766 he copied out the details of all the various processes in two books, which were thenceforth kept in the factory's archives. A series of extracts from Hellot's two books published here give information on the composition of the frit, of the plasticizer (or body ), of the binder (or chymie ), of the transparent glaze and some of the colors as well as methods of preforming joints (for spouts, handles, etc.), of firing, and of decoration. -- AATA