Niagara Falls 



1894 The chief piece of work in connection with the power installa- 



e ueur tion has been the construction of what, in almost any other situa- 

 tion, would be termed the tailrace. In this case the head utilized 

 is so great that what is ordinarily understood by a tailrace would 

 be an artificial chasm of abysmal proportions that would almost 

 require illumination other than the natural to be visible to the 

 bottom at midday. Instead, a tunnel has been excavated, of 

 which the dimensions are so remarkable as to make it unique 

 among engineering exploits of the kind. 



The location of the power house, on account of difficulty in 

 acquiring sufficient adjacent lands and rights of way and for 

 other reasons, is not very close to the falls. The Cataract Con- 

 struction Company has established itself about a mile and a half 

 above the American Fall, and has dug a canal of considerable 

 width, of a depth of twelve feet, and length fifteen hundred feet. 

 Along its edge for a distance of at present one hundred and forty 

 feet is dug a great trench or slot one hundred and sixty feet down, 

 with arrangements in the form of gates in the masonry wall 

 separating it from the canal, by which water may be admitted to 

 penstocks placed vertically in the slot and supplying the turbine 

 wheels. A penstock, as many of our readers are aware, is a great 

 tube, usually, in these days, of boiler plate, of a diameter running 

 up, it may be, to thirteen feet, conveying water under head into 

 the wheel case in which the turbine revolves. 



In the present instance the penstocks, which are seven and a 

 half feet in diameter, seem very small, considering that they each 

 supply a pair of wheels of five thousand horse power, but that is 

 on account of the enormous pressure under which the wheels 

 work, giving a greater power for a given volume of water than 

 with the smaller heads more commonly used. 



The turbines discharge their waste water into the tunnel above 

 referred to, which is no less than six thousand seven hundred feet 

 long, and which discharges into the chasm below the falls just 

 past the Suspension Bridge. 



The details of this tunnel, which was excavated through three 



948 



