SOAP AXD ITS USES
SOAP AXD ITS USES.—A soap is a compound of a fatty acid and an alkali. The alkalis in common use are sodium (soda) and potassium (potash). “Hard-water soaps,” or “hard soaps,” contain the alkali sodium; “soft-water soaps,” or “soft soaps,” contain potassium. The fat or oil used in each kind of soap may be the same. Coconut oil is the chief oil used, being added to tallow, which is the chief ingredient, but all animal and vegetable fats and oils procurable in quan¬tity are employed in the manufacture of soaps. The nature of the fat used markedly affects the consistency and quality of the soap.