2?.« AGRICULTURAL mGINEERING 



coming through the ground. The knives tear the weeds 

 out and the rake behind drags them free of the soil and leave* 

 them on the surface to be destroyed by the sun. The drag- 

 ging action of the pulverizer is also very good in leveling an 

 uneven surface. The draft of the pulverizer is less than 

 that of the disk harrow, an eight-foot pulverizer drawing 

 about as hard as a six-foot disk harrow. 



QUESTIONS 



1. What is the work of the smoothing harrow? 



2. Describe the difference in construction between the adjustable 

 tooth harrow and the lever harrow. 



3. Describe some of the important constructional features of the 

 smoothing harrow. 



4. Describe the construction of the spring-tooth harrow, and under 

 what conditions it will render the best service? 



5. Why is the harrow cart useful and what should be its construc- 

 tion? 



6. For what work is the disk harrow adapted? 



7. Describe some of the general features of the construction of the 

 disk harrow. 



8. What are the three general types of disk harrows? 



9. Describe the plow-cut disk blade. The alfalfa harrow. 



10. What is the purpose of the scrapers on a disk harrow? 



11. Why are the bearings important on a disk harrow? 



12. Of what use is a tongue truck? 



13. Describe the construction of harrow attachments for plows. 



14. Describe three types of land rollers. 



15. Explain some of the important points to be considered in select- 

 ing a land roller. 



16. To what purpose is the pulverizer adapted? 



17. Describe the construction of the curved-tooth pulverizer. 



