.ELECTRICAL ENERGY. 213 



sibility of the complete shut down of such a station, we have reached 

 such a point in the construction of machinery, both electric and me- 

 chanical, that with a proper reserve, a careful system of duplex steam 

 piping, and with fireproof construction of the station such a possi- 

 bility may be disregarded; while the batteries would look out for any 

 momentary interruption »on the feeders. 



CONTINUOUS CURRENT LOW VOLTAGE DISTRIBUTION. 



Some of the most important stations supplying incandescent lamps 

 are operated on the three-wire continuous current system. In the last 

 few years a considerable advance has been made in the sale of power 

 for motors from these stations, and this has increased the revenue and 

 has given better average output. The tendency in this country has 

 been in the direction of using storage batteries in such stations, and 

 abroad practically every continuous current station uses batteries. As 

 in the case of traction systems, it has been the custom in large cities to 

 build a number of separate stations instead of building a single plant 

 and distributing from it. The batteries have been placed in the stations 

 themselves, and no attempt has been made to decrease the amount of 

 copper used by employing a number of centers of distribution and giv- 

 ing the main feeders a steady load. The same considerations that apply 

 to stations for traction work will also apply to stations used to supply 

 lights, and the same methods of distribution may be used. It would 

 unquestionably be more economical in many instances to use single sta- 

 tions to transmit power from these stations to centers of distribution, 

 where batteries may be located and to distribute from these centers on 

 a three-wire system. A case in point is the system used at Budapest, 

 where the energy is distributed from the central station to rotary trans- 

 formers at substations, these rotary transformers feeding batteries, cur- 

 rent being distributed from these batteries on a three- wire system. The 

 reports of the operation of this station show that it is both economical 

 and successful, and it might well be copied by some of the companies 

 in this country. The gross receipts of some of the large illuminating 

 companies bear such a large proportion to the company's stock that a 

 comparatively small saving in operation would mean a considerable 

 increase in the dividends, and there is no doubt in my mind that by 

 using one power station, with battery substations for distribution, the 

 operating expenses can be considerably decreased. 



ALTERNATING: CURRENTS FOR LIGHTING:. 



Alternating currents have been employed for lighting in this country, 

 and they have been especially valuable where a district is to be supplied 

 in which the distances are considerable as compared with the number 

 of customers. It has been almost the universal custom to supply small 

 transformers for each consumer, and while the average size of trans- 

 formers is greater now than it was a few years ago, yet they are com- 

 paratively small. No power has been supplied from such stations, and 



