QUESTIONS. I05 



155. How should manure-heaps be managed ? What should 

 be added ? 



156. What is said of human excrements ? 



157. Why are animal manures richer than vegetable ? 



CHAPTER VIII. 



MINERAL FERTILIZERS. 



158. What mineral fertilizers are mentioned ? 



159. How is lime made ? 



160. What is slaked lime ? What effect on it has long ex- 

 posure to air ? 



161. In what condition is the water in slaked lime ? Its 

 properties ? How does mortar harden ? 



162. What is the use of lime as a fertilizer ? 



163. What is marl ? How valued ? 



164. What is said of green-sand marl ? Composition of 

 marl ? 



165. What sort of lands are well suited for marl ? 



166. What is gypsum ? What effect has heat upon it ? 

 How does it harden ? Its use ? 



167. How found ? Its properties ? How applied ? 



168. Why does it not injure seeds ? Why should it not be 

 mixed with superphosphate ? 



169. What is common salt ? How does it act ? 



170. What are salts ? What is said of the utilization of 

 waste products ? 



171. How much potash in the ashes of the oak ? Beech ? 



172. Why are ashes a good fertilizer? 



173. What is a compost ? How made ? 



174. What directions are given by Pendleton for compost- 

 ing with cotton-seed ? 



175. How can a good compost be made from materials on 

 every farm ? 



176. What does Professor Ville call a " complete manure "? 



