144 TUMBLl >EBRJNG 



independent pumps are very satis factor} 

 will run r there is steam pressure enough in the 



boiler to move the piston in the pump. They arc 

 ranged generally to heat the feed water and are not 



eful of steam. In fact, so far as economy is con- 

 cerned it does not matter particular!; :ype of boiler 

 feeder is employed for traction engine purposes. 



Injectors of both, the single and double tubed t 

 have been used and are used widely. They are simple, 

 easy to take care of, and are ready to work at a moment's 

 notice whenever the steam pressure is within their r 

 of action. They are singularly free from complex n 

 ing parts and are not difficult to repair. 



Nearly all injectors are built on the same plan. In 

 fact, there is so little difference between the injectors that 

 are on the market today, and those that were first built. 

 that it is almost safe to say there has been no marked 

 improvement in them since the beginning. This is not 

 strictly true, but it shows that the injector was very -well 

 perfected by the original inventor. All of the injc* 

 now offered are well proportioned and suitable for the 

 purpose intended. The best one to buy, perhaps, is the 

 one that can be the most easily attached. In general, 

 I would advise using the same style of injector when- 

 ever a new one has to be ordered. For traction engine 

 work the automatic injector is the only one worth con- 

 sidering. The characteristic feature of the automatic in 



