ENGINE No. 56. 225 



Engine No. 56 is a tandem compound with horizontal jack- 

 eted cylinders and reheating receiver. Steam is supplied to 

 the bottom of each cylinder, and the jacket spaces form a 

 thoroughfare through which it passes to the steam chest at the 

 top. The jackets are drained by traps which discharge to 

 waste. A jet condenser is used, with an independent steam- 

 driven air-pump, which is supplied from an independent boiler. 

 Steam is taken from horizontal return tubular boilers, and 

 it contained 0.8 % of moisture at a point near the throttle 

 valve. The valves and pistons were found to be in fair condi- 

 tion, but not the best. The load consisted of an electric gene- 

 rator placed on the driving-shaft, which for the test supplied 

 current to a water rheostat. 



This is an example of a Corliss engine running at compara- 

 tively high rotative speed and piston speed as well, which is gen- 

 erally considered to be one of the conditions which contribute 

 to good economy. The result, however, is nothing unusual. 

 The conclusion cannot fairly be drawn from this test that such 

 a speed produces no advantage ; for there were other conditions 

 pertaining to the work, such as the pressure and vacuum, which 

 were unfavorable to economy. 



