402 PRODUCTIVE FARMING 



Animal power is often used on sweeps for operating -balers, 

 grinders, and some other machines. Such power has long 

 been used on tread mills for operating belt machines for such 

 work as sawing wood, grinding, threshing, etc. Bulls, calves, 

 sheep, and heavy dogs are used on tread mills for light work 

 cream separation, churning, milking, washing clothes, pump- 

 ing water, etc. 



EXERCISE. The students should visit one or more farms 

 having a tractor, motor truck or stationary engine. If 

 possible, study belting systems, uses of power, parts of en- 

 gines, troubles, etc. At some places study lighting systems, 

 other forms of power, etc. 



REVIEW. 



1. For what work are motor trucks used by farmers in your region? 



2. What sizes of motor trucks have you seen? 



3. Give the advantages of using tractors for plowing. 



4. What are the disadvantages? 



5. Discuss the sizes of tractors for farm work. 



6. What are the factors which enter into the cost of plowing 

 with tractors? 



7. What is the average fuel cost per acre? 



8. What things cause this to vary? 



9. How much grease and oil are required? 



10. What is the cost of repairs? What should be allowed for 

 depreciation? 



11. Give some examples of cost of tractors and plows, and figure 

 the necessary annual interest charge. 



12. What other farm implements are sometimes drawn by tractors 

 in your region? 



13. What other lines of farm work are done by tractors? 



14. Ask some farmer the necessary horse power for operating each 

 of the belt machines on farms. 



15. Discuss the need of competent operators for tractors. 



16. What are the four chief essentials in operation of gas engines? 



17. What is the carburetor? Discuss its uses. 



18. What does the black smoke from the exhaust indicate? 

 Blue smoke? 



19. Tell of the importance of good compression. 



20. What sources of current are used for ignition of gas engines? 



21. Describe the make-and-break system, and tell how to test it. 



22. Describe the jump-spark system and tell how to test it. 



23. Discuss the importance of proper valve action. 



24. What engine troubles have you observed? 



25. What engine troubles are most common? 



26. For what work may electric motors be used on farms? 



