The general tendency of this period appears to have taken the form of improving and developing the methods of the alchemists; 1 The definite distinction between potash and soda was first established by Duhamel de Monceau (1700-1781).
Duhamel du Monceau.
But the two substances were generally confounded as "fixed alkali" (carbonate of ammonia being "volatile alkali"), till Duhamel du Monceau in 1736 established the fact that common salt and the ashes of seaplants contain the same base as is found in natural deposits of soda salts ("mineral alkali"), and that this body is different from the "vegetable alkali" obtained by incinerating land plants or wood (pot-ashes).
Duhamel de Monceau, in 1735, left no doubt upon the subject.
Duhamel and F.