194 nature's /Piracies. 



the heat and warms the power-house, on the 

 principle of a hot-air furnace. This great 

 machine which, in a way, is so simple in its 

 construction when in action conveys to the 

 mind of the beholder a sense of wonderful 

 power. It is only when we stand in the pres- 

 ence of such exhibitions as may be seen in this 

 power-house, devised and executed by the 

 genius of man, and in that greater presence, 

 the mighty Falls of Niagara, that we get some- 

 thing of a conception of the power of the silent 

 yet potent energy of the great king of daylight, 

 the sun. 



There are very many in ten sting details that 

 work in connection with this great power- 

 plant, some of which we will describe, in a gen- 

 eral way. 



Standing within a few feet of each one of 

 the great dynamos is a very beautifully con- 

 structed piece of machinery called the gov- 

 ernor. The governor regulates the speed of 

 the dynamos by partially opening and closing 

 the water-gates that regulate the flow of water 

 into the turbines. The question may be asked, 

 why is there any regulation needed, if there is 

 always an even head of water? There are two 

 reasons one because the load on the dynamo 

 is constantly changing, and another that the 

 head of water changes, although this latter 

 fluctuation is in long periods. If the circuit 

 leading out from the dynamo is broken, the 



