Soda has a great affinit}^ for water ; and when wet, a combination takes place which allows some of the carbonic acid gas to escape. This ma}^ easily be seen by the effer- vescence which occurs when soda is dissolved in hot water. This, the old way of using soda, was theoretically wrong, as much of the gas was lost ; yet practically good results were obtained, because the saleratus formerly used was much stronger than the bicarbonate of soda of to-day, and could well be weakened. The Boston Cook Book. 8i Soda alone, when mixed with wet dough, will give off gas enough to raise the dough ; but it leaves a strong alkaline taste and a greenish yellow color, and, being poisonous, must be neutralized by an acid, or else its use is not ad- missible. The best acid for this purpose is one w4iich does not liberate the gas instantly on contact with the soda, before the heat can fix the air cells, and also the one which leaves no unwholesome residue. Muriatic Acid^ which is sometimes used, would be the best, as it leaves only common salt as a residue ; but the gas is liberated instantly, and onlj' a skilled hand can mix the bread and place it in the oven without losing much of the gas. Cream of Tartar^ which is tartaric acid combined with potash, and is obtained from the crystals or argols which collect in w^ine casks, is preferred by chemists. Being only slightl}^ soluble in cold water, it unites with soda only when heated, and the gas is not all liberated until the mixture is in the oven. The residue from the union is Rochelle salt, which is not injurious taken occasionally in small quantities. The objections to cream of tartar are these : being very expensive (the price varying with the grape crop), it is often adulterated with alum and other harmful substances ; and the proportions of soda and cream of tartar are often guessed at instead of being ac- curatel}^ measured. The only safe wa}^ to use these chemi- cals is to purchase cream of tartar of a reliable chemist, and to measure carefully one level teaspoonful of soda to two full teaspoorfuls of cream of tartar for 07ie quart of flour. It takes a trifle more than twice the quantity of cream of tartar to make the reaction complete. The soda must be finel}^ pulverized before measuring ; rub it on the board with a knife, measure, and then sift through the finest wire strainer into the flour. Sifting with the flour through an ordinary flour sieve is not enough. Cream of tartar does not become lumpj^ like soda ; but it is better to sift it, and salt also, into the flour, and then sift all together two or three times. There is no greater abomination in cooked 6 82 The Boston Cook Booh food than a spot of soda, even if it be but the size of a pin-head, and no one should excuse such negligence.

AI-modernized reading of the original text

Soda has a great affinity for water ; and when wet, a combination takes place which allows some of the carbonic acid gas to escape. This ma}^ easily be seen by the effervescence which occurs when soda is dissolved in hot water. This, the old way of using soda, was theoretically wrong, as much of the gas was lost ; yet practically good results were obtained, because the saleratus formerly used was much stronger than the bicarbonate of soda of to-day, and could well be weakened. The Boston Cook Book. Soda alone, when mixed with wet dough, will give off gas enough to raise the dough ; but it leaves a strong alkaline taste and a greenish yellow color, and, being poisonous, must be neutralized by an acid, or else its use is not admissible. The best acid for this purpose is one which does not liberate the gas instantly on contact with the soda, before the heat can fix the air cells, and also the one which leaves no unwholesome residue. Muriatic Acid, which is sometimes used, would be the best, as it leaves only common salt as a residue ; but the gas is liberated instantly, and only a skilled hand can mix the bread and place it in the oven without losing much of the gas. Cream of Tartar, which is tartaric acid combined with potash, and is obtained from the crystals or argols which collect in wine casks, is preferred by chemists. Being only slightl}^ soluble in cold water, it unites with soda only when heated, and the gas is not all liberated until the mixture is in the oven. The residue from the union is Rochelle salt, which is not injurious taken occasionally in small quantities. The objections to cream of tartar are these : being very expensive (the price varying with the grape crop), it is often adulterated with alum and other harmful substances ; and the proportions of soda and cream of tartar are often guessed at instead of being accuratel}^ measured. The only safe way to use these chemicals is to purchase cream of tartar of a reliable chemist, and to measure carefully one level teaspoonful of soda to two full teaspoonfuls of cream of tartar for one quart of flour. It takes a trifle more than twice the quantity of cream of tartar to make the reaction complete. The soda must be finely pulverized before measuring ; rub it on the board with a knife, measure, and then sift through the finest wire strainer into the flour. Sifting with the flour through an ordinary flour sieve is not enough. Cream of tartar does not become lumpj^ like soda ; but it is better to sift it, and salt also, into the flour, and then sift all together two or three times. There is no greater abomination in cooked The Boston Cook Booh food than a spot of soda, even if it be but the size of a pin-head, and no one should excuse such negligence.

Mrs. Lincoln's Boston cook book