AND AGRICULTURE. 



43 



The following table shows the quantity of 

 ashes left after burning one thousand pounds of 

 hay, made from the different grasses named, and 

 the composition of the ashes of the several kinds 

 of grass. (See Appendix, 28.) 



Now, you will see that unless the soil contains 

 all the substances found in the ashes of plants, 

 the plants cannot grow perfectly ; and, although 

 some of those substances are only found in very 

 small quantities in the plant, yet their presence 

 is necessary for its health and life. 



Questions. What does the table show? How many 

 pounds of ashes in one thousand pounds of rye grass ? In 

 red clover ? In white clover ? In lucerne ? Are sub- 

 stances, found only in very small quantity in the plant, 

 necessary in the soil ? 



