CHAPTER XXIV. 



NIAGARA FALLS POWER APPLIANCES. 



In the last chapter I described some of the 

 appliances used in connection with the power- 

 house. There are many things that are com- 

 monplace as electrical appliances when used 

 with currents of low voltage and small quan- 

 tity, that become extremely interesting when 

 constructed for the purpose of handling such 

 currents as are developed by the dynamos 

 used at Niagara. For instance, it is a very 

 commonplace and simple thing to break and 

 close a circuit carrying such a current as is 

 used for ordinary telegraphic purposes, but 

 it requires quite a complicated and scien- 

 tifically constructed device to handle currents 

 of large volume and great pressure. If such a 

 current as is generated by a dynamo giving 

 out 5000 horse-power under a pressure of 2200 

 volts should be broken at a single point in a 

 conductor, there would be a flash and a report, 

 attended \\ith such a degree of heat and such 

 power for disintegration that it would destroy 

 instrument 



The circuit-breakers used at Niagara are 

 199 



