50 Kansas Academy of Science. 



Ten, perhaps fifteen, years ago began what may be called 

 the up-to-date period of power development. As might be 

 expected, efforts in this period have been directed mainly to 

 producing better efficiencies from machinery already developed, 

 yet this period has produced two entirely new power motors 

 and the experimental investigation of a third. 



In water-power development, after the successful completion 

 of the American plant at Niagara, many other projects were 

 undertaken. These are of three general classes : medium head 

 plants like the one just mentioned; high head plants like those 

 in California, where the fall is several hundred feet; and low 

 head plants like that at Keokuk, where the head is only about 

 thirty feet. At Niagara the turbine wheels are 5 feet 4 inches 

 in diameter and at Keokuk they are 16 feet 2 inches, while for 

 the high heads that are developed on the Pacific coast an en- 

 tirely different type, known as the impulse wheel, is used. 

 Progress has been along two main lines : the perfection of 

 wheels to give best efficency for these different sets of con- 

 ditions, and increase in transmission voltages. We have ad- 

 vanced along these two lines to the point where any sort of a 

 water power may be successfully developed, from an immense 

 volume with little fall to a small volume with a high fall. 

 Voltages have increased from 22,000 to 150,000, and power may 

 be successfully carried 150 miles or more, so that the industry 

 and the town is in a sense independent of the location of the 

 power site. 



In steam engineering there has been a return from the 

 complicated triple- and quadruple-expansion engine to the older 

 two-stage compound type. This has been made possible by 

 superheating the steam, that is, raising it to a temperature 

 above that due to its pressure. Development and change in 

 the use of steam turbines has been so rapid in the last decade 

 that it is almost impossible to say what the best practice is ai 

 the present time. We are able to distinguish two directions in 

 which changes are being made, but whether they indicate per- 

 manent progress the future only can "reveal. One of these 

 is increase in size. Where ten years ago 5000 horsepower was 

 regarded as a monster unit it is now regarded as a small one, 

 30,000 horsepower being the large one. The other direction in 

 which change is being made is in mixing the types, impulse 

 and reaction in a single machine. This enables the designer to 

 take better advantage of the high and low pressures of the 



