Applied Science 811 



included the sinking, through the rock, of great vertical rec- 

 tangular pits, 150 or more feet deep, at the bottom of which 

 turbines are located, and the driving of long tunnels to carry the 

 water away from the pits after it has done its work in the turbines. 

 The penstocks feeding the latter are attached to the sides of the 

 pits, and the turbines are connected by long shafts with the rotat- 

 ing parts of their respective generators in the power-house far 

 above. 



Great Engineering Feats 



It is impossible to even mention here the many great en- 

 gineering feats performed at Niagara in connection with the 

 various power schemes, but passing reference may be made to 

 two notable discharge tunnels driven 7,000 and 2,000 feet re- 

 spectively through the rock. The former is reputed to be one 

 of the largest tunnels in the world as regards size of section, 

 and it is otherwise interesting as having its exit behind the water 

 curtain of the Canadian Falls. Taking schemes separately, the 

 latest is undoubtedly the most imposing, as it makes use of a 

 total fall of over 300 feet, or about twice that utilised by most 

 of the earlier installation. The Falls are in this case "turned" 

 by a canal, l2^/ 2 miles in length, which draws water from the 

 Welland River entering the Niagara River a long way above 

 the Falls, and leads it to near Queenston, below the lower rapids, 

 where a huge power-house is being erected at the water's edge. 

 This will ultimately contain ten units of 40,000 electrical horse- 

 power each. The construction of the canal required the excava- 

 tion of over 13,000,000 cubic yards of material, mostly rock ; and 

 so great is the flow through the new channel that the current in 

 the Welland River has been reversed beween the junction with 

 the Niagara River and the entrance to the Canal. 



How Water Turbines Work 



We can give here only a brief description of the water tur- 

 bines used at Niagara. The type mounted at the bottom of the 



