68 CHEMISTRY, GEOLOGY 



you see that, although so corrosive and destruc- 

 tive to life, it contains the same elements as the 

 air we breathe, but mixed in different propor- 

 tions. 



The nitrate of soda, by decomposition, yields 

 nitrogen and soda to the growing crops. About 

 one and a half hundred weight may be spread 

 over each acre. 



Sulphate of soda is commonly known as glau- 

 ber salts. It is composed of sulphuric acid and 

 soda. Sulphuric acid is sulphur combined with 

 oxygen. It is often advantageously applied as 

 a top-dressing to grass lands, turnips, and to 

 young potato-plants. Seventy pounds of dry 

 sulphate of soda contain forty pounds of sul- 

 phuric acid and thirty-one pounds of soda. 



Common salt is a combination of soda and 

 muriatic acid, the acid commonly known as spir- 

 its of salt. It may be applied as a top-dressing. 

 or mixed with the common manure of the yard, 

 or in solution in the water used for slaking 



Questions. What does nitrate of soda yield to the 

 soil ? Of what is the sulphate of soda composed ? For what 

 is it useful as a manure ? What are the proportions of the 

 components of sulphate of soda ? Of what is common salt 

 composed ? 



