388 AGRICULTURAL ENGINEERING 



The lubricator consists of a tank of oil connected under- 

 neath with a short column of water. The excess weight of 

 water over that of the steam when applied at the bottom of 

 the oil reservoir enables the oil to be fed through a small 

 valve, a drop at a time. The accompanying illustration 

 shows the construction of a lubricator. 



QUESTIONS 



1. How is the farm steam engine usually mounted? 



2. Explain the principle of the steam engine. 



3. Describe the compound engine, and what advantage does it 

 offer? 



4. What are the merits of a double engine? 



5. Why is it necessary for a steam engine to have a fly wheel? 



6. Describe the action of the governor. 



7. Describe the action of the steam engine lubricator. 



8. What other oiling device is in common use? 



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