THE CONQUEST OF NATURE 



It consists of a large number of series of small blades, 

 each series arranged about a drum which revolves. 

 Between the rings of revolving blades are adjusted cor- 

 responding rings of fixed blades, which project from 

 the casing to the cylinder, and by means of which the 

 steam is regulated in direction, so that it strikes at the 

 proper angle against the revolving blades of the turbine. 



In practise, three series of cylindrical drums are used, 

 each containing a large number of rings of blades of 

 uniform size; but each successive drum having longer 

 blades, to accommodate the greater volume of the ex- 

 panding steam. The steam is fed against the first series 

 of blades in gusts, which may be varied in frequency 

 and length to meet the requirements of speed. After 

 impinging on the first circle of blades, the steam passes 

 to the next under slightly reduced pressure, and the 

 pressure is thus successively stepped down from one 

 set of blades to another until it is ultimately reduced from 

 say two hundred pounds to the square inch, to one 

 pound to the square inch before it passes to the condenser 

 and ceases to act. 



There is thus a fuller utilization of the kinetic energy 

 of the gas, through carrying it from high to low pres- 

 sure, than is possible with the old type of cylinder-and- 

 piston engine. On the other hand, there is a constant 

 loss due to the fact that the blades of the turbine can not 

 fit with absolute tightness against the cylinder walls. 

 The net result is that the compound turbine, as at pres- 

 ent developed, appears to have about the same efficiency 

 as the best engine of the old type. 



One capital advantage of the turbine is that it keeps 



