450 THE KENNEDY PIPE SCKAPER — DOANE. 



that it could not be traced, and the water passing through it 

 accumulated ahead of it It is necessary that some water shall 

 pass through to carry off the dirt as it is scraped off. In this case 

 the water could not run off ahead, and the dirt piled up. The 

 pressure available behind could not overcome the resistance of 

 this load of dirt and water and the scraper became lodged in the 

 pipe. 



Profiting by experience, precautions were taken last Novem- 

 ber (1893) to prevent a repetition of the trouble. The scrapers 

 were made smaller in diameter and the pistons made tighter 

 to prevent the passage of water. The blow-off was left open 

 so that the pipe would be empty and the run through that 

 portion of the main cleaned the previous year was made with- 

 out any difficult}^ The blow-off was closed immediately after 

 the scraper passed so that the full pressure would be exerted on 

 the piston. The progress of the machine was slow, as the incrus- 

 tation was very thick and at times it was difficult to hear it at 

 all. However, it continued steadily up the hill and passed the 

 sunnnit, reaching the end of the 20 inch pipe, 6,712 feet from the 

 dam, in about one hour from the time of starting. No difficulty 

 is anticipated in future, as the pipe will be cleaned every year. 



