36 ROI 



cess was generally known, a great deal of trouble 

 annoyance could be avoided. 



It will not be necessary to describe other sfr 

 pumps. If you know how to run the cross head pump 

 you can run any of the others. Some engines have a 

 cross head pump only. Others have an independent 

 pump. Others have an injector, or inspirator, and .- 

 have both cross head pump and injector. I think a farm 

 engine should he supplied with both. 



It is neither wise nor necessary to go into a detailed 

 description of an injector. The young reader will be 

 likely to become convinced that if an injector work- 

 five minutes, it will continue to work, if the conditions 

 remain the same. If the water in the tank does n< 

 come heated, and no foreign substance is permitted to 

 enter the injector, there is nothing to prevent its work- 

 ing properly as long as the conditions are within the 

 range of a good injector. It is a fact that with all in- 

 jectors as the vertical distance the injector lift is in- 

 creased, it requires a greater steam pressure to start the 

 injector, and the highest steam pressure at which the 

 injector will work is greatly decreased. If the feed water 

 is heated, a greater steam pressure is required to start 

 the injector and it will not work with as high steam pres- 

 sure. The capacity of an injector is always decreased 

 as the lift is increased, or the feed water heated. To 



