204 1Rature'0 



produce the painful sensation that the sec- 

 ondary coil did. 



We have now described the principle of a. 

 transformer as it is worked out in an ordi- 

 nary induction-coil. As has been stated, at 

 Niagara Falls the current comes from the 

 dynamos with an electromotive force or pres- 

 sure of 2200 volts. For some purposes this 

 voltage is not high enough, and for other pur- 

 poses it is too high; therefore it has to be 

 transformed before it is used! For some pur- 

 poses this transformation takes place in the 

 power-house, and for others it takes place at 

 the establishment where it is used. For in- 

 stance, take the current that is sent to Buffalo, 

 a distance of from twenty to thirty miles. The 

 current first runs to a transformer connected 

 with the power-house, win-re it is "stepped- 

 up " (to use the parlance of the craft) from a 

 voltage of 2200 to 10,000. It is carried to 

 Buffalo through wire conductors that are 

 strung on poles, and is there " stepped-down " 

 again through another transformer to the volt- 

 age required for use at that place. The object 

 of raising the voltage from 2200 to 10,000 in 

 this case is to save money in the construction 

 of the line of conductors between the two 

 points. If the voltage were left at 2200 the 

 conductors remaining the same as they are 

 now the loss in transmission would be very 

 great, owing to the resistance which these 



