228 THE UTILIZATION OP NIAGARA. 



of marble or mahogany, not unlike a big front door with lots of knobs, 

 knockers, and keyholes on it; but at the Niagara power house it takes 

 the form of an imposing platform, or having in mind its controlling 

 functions, we may compare it to the bridge of an ocean steamer, 

 while the man in charge or handling the wheels answers to the navi- 

 gating officer. The ingenious feature is employed of using compressed 

 air to aid in opening and closing the switches. The air comes from a 

 compressor located at the wheel pit and driven by a small water motor. 

 It supplies air to a large cylindrical reservoir, from which pipes lead 

 to the various switches, the pressure being 125 pounds to the square 

 inch. Another interesting point is that the measuring instruments on 

 the switch board do not measure the whole current, but simply a derived 

 portion of determined relation to that of the generators. All told, 

 less than a thirtieth of a horsepower gives all the indications required. 

 To the switch board, current is taken from the dynamos by heavy insu- 

 lated cable, and it is then taken off by huge copper bus bars which are 

 carefully protected by layers of pure Para gum and vulcanized rubber, 

 two layers of each being used; while outside of all is a special braided 

 covering, treated chemically to render it noncombustible. The calcu- 

 lated losses from heating in a set of four bus bars carrying 25,000 horse- 

 power, or the total output of the first five Niagara generators, is only 

 10 horsepower. About 1,200 feet of insulated cable have been supplied 

 to carry the current from the dynamos to the switch board in the power 

 house. It has not broken down until between 45,000 and 4S,0U0 volts 

 of alternating current were applied to it. There are 427 copper wires 

 in that cable, consisting of 6 !. strands laid up in reverse layers, each 

 strand consisting of 7 wires. Next to the strand of copper is a wall 

 of rubber one-quarter inch thick, double coated. Over this is wrapped 

 absolutely pure rubber, imported from England and known as cut 

 sheet. Then come two wrappings of vulcanizable Para rubber, next 

 there is a wrapping of cut sheet, and on top of that are two more rub- 

 ber coats. This is then taped, covered with a substantial braid, and 

 vulcanized. The object in using the cut sheet is to vulcanize it by con- 

 tact, in order to make it absolutely water tight. This cable weighs 

 just over 4 pounds to the foot, of which 3 pounds are copper and 1 

 pound insulation. 



We have thus advanced far enough to get our current on to the bus 

 bars, and the next step is to get it from them out of the power house. 

 This final work is done by extending our bars, so to speak, and carry- 

 ing them across the bridge over the canal, into what is known as the 

 transformer house. It is here that the current received from the other 

 side of the canal is to be raised in potential, so that it can be sent great 

 distances over small wires without material loss. Meantime we may 

 note that the Niagara Tails Power Company itself owns more than a 

 square mile around the power house, upon which a large amount of 

 power will be consumed in the near future by manufacturing establish- 



