T.OO SCIENTIFIC AGRICULTURE. 



65. Which crop mentioned in the table has the most starch ? 

 Albuminoids ? Fat ? Woody fibre ? Ash ? 



66. Are the ash constituents important ? What becomes 

 of the products of combustion ? What does a plant carry from 

 the soil ? What is the ultimate effect ? 



67. What does Liebig mean by a system of spoliation ? 

 What elements are scarcely ever deficient ? In what condition 

 may they exist ? How can this be remedied ? 



68. What elements are likely to be deficient ? Can the soil 

 produce when any of the essential elements of plants are ab- 

 sent? 



69. What does chemistry teach the farmer ? For what 

 must it not be held responsible ? 



70. By what must the fanner be guided ? 



CHAPTER IV. 

 THE COMPOSITION AND PROPERTIES OF THE ATMOSPHERE. 



71. What does the atmosphere contain ? 



72. Is the air uniform in composition ? In what condition 

 are its constituents ? 



73. What is said of watery vapor ? Whence does it rise ? 

 What does it form when condensed ? 



74. The character of nitrogen ? Of oxygen ? The effect 

 of carbon dioxide on animals ? On plants ? 



75. How is carbon dioxide formed ? What prevents its ac- 

 cumulation in the atmosphere ? What change takes place in 

 it when absorbed by the leaves of plants ? 



76. How does carbon dioxide get into the leaves ? Through 

 what influence is it decomposed ? 



77. How much carbon dioxide exists in the atmosphere ? 

 What says a distinguished chemist ? 



78. How much ammonia is in the atmosphere ? 



79. To what is the atmosphere adapted ? What benefits 

 are derived from it ? 



