Baking Powder, a combination chemically prepared of tartaric acid and bicarbonate of soda, mixed with flour for the making of bread, biscuits, cakes, etc. The powder, when water is added, causes the bread to rise, as in the olden method of making bread by the fermenting of yeast. Some bakers substitute the bicarbonate of ammonia for that of soda, which is unobjectionable; though the use of alum in lieu of tartaric acid is objectionable if one desires to have wholesome bread.