1906.] oil The Steam Tarhine on Land and at Sea. 327 



nozzles will be about 2000 feet per second, and the peripheral velocity 

 of wheel about 400 feet per second ; and at each operation the steam 

 is expanded through one-fourth of the whole range, and at each it is 

 brought to rest before flowing to the next chamber through the jets. 



A great many other varieties of the turbine have been proposed, 

 and some have received a limited application. The Rateau, the Reidler 

 Stumpf, the Zoelly, the Escher Wyss, and many others, might be 

 mentioned as varieties of the three fundamental turbines we have con- 

 sidered ; indeed in some cases the variation would appear to have been 

 only a retrograde step, and represents some discarded form tried by 

 one of the originators of the three fundamental types. 



As far as we can gather from the history of the steam turbine, it 

 may be said broadly that all the chief features at present in use in 

 turbines have been suggested or described in the rough by experi 

 menters long ago in the hundred and more patents prior to 1880. 



For instance. Hero of Alexandria, B.C. 130, made a reaction 

 wheel. 



William Gilmore first suggested the compound steam turbine in 

 1837. 



Matthew Heath first enunciated the principle of the diverging 

 conical jet in 1838. 



James Pilbrow in 1842 used cupped buckets, and suggested a 

 sinuous treatment of the steam. 



Robert Wilson developed the compound steam turbine to a con- 

 siderable extent in 1848. 



It would take too long to trace the initiation of each idea, but 

 we may say, in the light of recent experience, that most, if not all, the 

 designs showed a want of knowledge of the properties of steam and 

 materials, and could not have given a satisfactory performance. 



Let us again recur to the compound turbine, and look more 

 closely into the principles of its working, and more particularly 

 consider the course of the steam in its passage through the vanes or 

 blades of the engine. 



Viewing the turbine as a whole we see that the steam passes 

 through the forest of fixed and moving blades just as water flows 

 from a lake of higher level through a series of rapids and intervening 

 pools to a lake of lower level. The boiler corresponding to the lake 

 of higher level and the condenser to that of lower level. 



In the flow through the turbine the steam is repeatedly gathering 

 a little velocity from the small falls of pressure, which is as soon 

 checked and its energy transferred to the blades, over and over again ; 

 50 to 100 times is this repeated before it is fully expanded and 

 escapes into the condenser. 



The number of blades in a steam turbine is very great ; in a 

 2000 horse-power engine it may be from 20,000 to 50,000 and the 

 surface speed of the several barrels of the turbine will be from 150 to 

 300 feet per second. In such an engine it is arranged that the lineal 



