398 Telephone Systems of the Continent of Europe 



mitters, test, and drops. The accumulators, which have a capacity 

 of 127 ampere-hours, are charged by a i2-h.p. gas-engine driving 

 a i4o-volt dynamo. The smaller battery is used in parallel for 

 the transmitters, and in series for its other work. The necessary 

 alternating current for ringing the subscribers' bells is provided 

 by means of an electro-motor driven by the accumulators. Two 

 opposing segments of the commutator are connected to two 

 insulated metal rings on the other end of the motor spindle, on 

 which rings collectors in connection with the ringing keys are 

 always pressing. As the opposing segments come alternately 

 under the + and brushes, the current in their rings is 

 reversed and the necessary alternations produced. This arrange- 

 ment is shown in fig. 140. The voltage required for ringing 



T 



FIG. 140 



being only 60, resistance has to be interposed between the motor 

 and the keys. 



Zurich is the most important telephonic centre in Switzerland, 

 although it is run closely by Geneva and Basle. At the end of 

 October 1894 there were 2,769 subscribers, together with thirty-five 

 trunk lines, operated by the switch -board. The population being 

 about 130,000, there are thus 2-13 telephones for each hundred 

 inhabitants. The operators are thirty-two in number, or one to 

 every eighty-six lines, besides which there are three girls occupied 

 in registering calls of various kinds that are subject to special 

 charges. The number of local connections from January i to 

 June 30, 1894, was only 809,807, while the trunk communications 

 mounted up to 233,213 more than a fourth. The number of 

 telegrams telephoned to the telegraph office was 8,842. It thus 

 seems that the effect of the Swiss local tariff is to reduce the 

 traffic, since during the period named the local talks amounted to 



