40 THE ELEMENTS OF PLANT FOOD 



is potassium stearate, oleate, and palmitate ; hard soap 

 is sodium stearate, oleate, and palmitate. 



The home method of making soft soap is as follows : 

 Fill a barrel with wood ashes. Pour water on the ashes 

 and allow it to percolate through the ashes and to pass 

 out through a hole near the bottom of the barrel into 

 a jar. This liquid is of a dark brown color, called lye. 

 This process may be continued till the ashes have given 

 up nearly all the potash that they contain. Pieces of 

 animal fats, usually wastes of the kitchen, are melted 

 in an iron kettle. After removing the parts that will 

 not melt, the oil is boiled with the lye till the soft soap 

 is formed. 



Alcohols 



Although there are numerous carbon compounds that 

 are properly called alcohols, there are but two which 

 are of general interest. They are ethyl alcohol and 

 methyl alcohol. 



Ethyl Alcohol (C 2 H-,OH). This is common alcohol, 

 that which is meant by most persons when using the 

 term. It is a clear liquid which burns with great heat. 

 Because of the abundance of H and the small amount of 

 C, it burns without smoke, therefore does not darken 

 articles heated in its flames. Ethyl alcohol is produced 

 by fermentation of sugar. A plant juice containing 

 sugar, that is, grape sugar, or glucose, when exposed 

 to the air loses its sweetness and changes into alcohol 

 and carbon dioxide. 



Glucose Alcohol Carbon dioxide 

 C 6 H 12 O 6 = 2 C 2 H 5 OH + 2 CO 2 



This change is caused by the action of small ferments, 

 called enzymes. The cells which secrete the enzyme 



