BAKING SODA 149 



By far the largest quantity of salt, however, comes from the 

 seas which no longer exist, but which in far remote ages dried 

 up and left behind them their burden of salt. Deposits of 

 salt formed in this way are found scattered throughout the 

 world, and in our own country are found in greatest abundance 

 in New York state. The largest salt deposit known has a 

 depth of one mile and exists in Germany. 



Salt is indispensable on our table and in our kitchen, but 

 the amount of salt used in this way is far too small to account 

 for a yearly consumption of 4,000,000,000 tons in the United 

 States alone. The manufacture of soap, glass, bleaching 

 powders, baking powders, washing soda, and other chemicals 

 depends on salt, and it is for these that the salt beds are mined. 



Baking soda. Salt is by all odds the most important sodium 

 compound. Next to it come the so-called carbonates of sodium, 

 that is, compounds of sodium in which carbon is present : first, 

 sodium carbonate, or washing soda ; and second, sodium bicar- 

 bonate, or baking soda. Washing soda is a compound of sodium, 

 carbon, and oxygen. Baking soda is a compound of sodium, 

 hydrogen, carbon, and oxygen. These are both obtained by 

 treating salt with ammonia and carbon dioxide. 



Since baking powder in some form is used in almost all homes 

 for the raising of cake and pastry dough, it is essential that its 

 helpful and harmful qualities be clearly understood. 



The raising of dough by baking soda bicarbonate of soda 

 is a very simple process. When soda is heated it gives off 

 carbon dioxide gas. You can easily prove this for yourself by 

 heating a little soda in a test tube, and testing the escaping gas 

 in a test tube of lime water. When flour and water alone are 

 kneaded and baked in loaves, the result is a mass so compact 

 and hard that human teeth are almost powerless to crush and 

 chew it. The problem is to separate the mass of dough or, 

 in other words, to cause it to rise and lighten. This can be 



