240 Eon. C. A. Parsons [Jan. 26, 



All end pressure from the steam was balanced by the two equal 

 series on each side of the inlet, and the revolving shaft lay on its 

 bearings revolving freely without any impressed force except a steady 

 torque urging rotation, the aggregate of the multitude of minute 

 forces of the steam on each blade. It constituted an ideal rotary 

 engine ; but it had faults. The comparatively high speed of rotation 

 that was necessary for so small a size of engine as this first example, 

 made it difficult to prevent, even with the bearings described, a 

 certain spring or whipping of the massive steel shaft, so that con- 

 siderable clearances were found necessary, and leakage and loss of 

 efficiency resulted. It was, however, perceived that all these defects 

 would decrease as the size of the engine was increased, with a corre- 

 sponding reduction of rotational velocity, and consequently efforts 

 were made towards the construction of engines of larger size, which 



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Flx£D BlhdeS. 



Moving Bluo! 



Fig. 1. — Fixed and Moving Blades of Turbine. 



resulted, in 1888, in several turbo-alternators of 120 horse-power 

 being supplied for the generation of current in electric lighting sta- 

 tions, and at this period the total horse-power of turbines at work 

 reached in the aggregate about 4000, all of which were of the parallel 

 flow type and non-condensing. 



In 1889, in consequence of partnership difficulties and the tem- 

 porary loss of patents, the radial flow type of turbines was reluctantly 

 adopted. This type of turbine consists of a series of fixed discs with 

 interlocking flanges at the periphery, forming, when placed together 

 coaxially, a cylindrical case, with inwardly projecting annular discs. 

 On the shaft are keyed a similar set of discs, the faces of the fixed and 

 moving disc lie a short distance apart. From the faces of the fixed 

 disc project the rows of guide-blades which nearly touch the moving 

 disc, and from the moving disc project the rows of moving blades 

 which nearly touch the fixed disc. 



