2OO Telephone Systems of the Continent of Europe 



calls to the small boards, and the connections are completed 

 through an intermediate section on which all the local lines are 

 multipled. The trunk tables are provided with sand-glasses on 

 the Swiss plan for checking the duration of conversations. The 

 arrangements are very carefully devised, but the speed and 

 economy obtained would be greater, and the chance of error less, 

 if the trunk girls had the local repeats directly at command. One 

 operator to two trunks appears superfluously luxurious. The 

 translators used are of the double- coil type with yoked cores, the 

 resistance of both primary and secondary being 1 70 ohms. 



To those who understand the possibilities of telephonic 

 switching in the direction of rapidity, and are accustomed to 

 think of demand and connection as a matter of three or four 

 seconds only, the methods adopted in Berlin appear strange, even 

 to the verge of incomprehensibility. The seven switch-rooms are 

 numbered from i upwards, and a subscriber is represented in 

 the list by two numbers, firstly that of his switch-room, secondly 

 that of his line, so that in the same town the same series of 

 numerals is repeated seven times and distinguished by an index 

 number, like so many logarithms. Indices, consisting of short 

 words differing widely in pronunciation such as the names of 

 colours, of jewels, of rivers, anything would be much more dis- 

 tinctive and less liable to be misunderstood than a constant 

 repetition of numerals. That confusion is apt to arise is obvious 

 from the rule which enjoins the calling subscriber to mention the 

 number and name of the switch -room to which the person he 

 wants is connected. Thus, to quote the rule, No. 3 switch-room 

 must be asked for in a ten-syllable formula, ' Amt drei, Oranien- 

 burgerstrasse.' The following indicates the steps of a Berlin con- 

 nection through one switch-room when the fates are propitious 

 and the course of telephony runs smooth. A wants B. 



Operation i. A takes one of his two telephones off its hook 

 and applies it to an ear. 



[He is instructed to do this, but is not told which. If he happens to take 

 the left-hand one and a stranger would be as likely as not to do so he cannot 

 ring the exchange, and naturally does not get any answer. It is true that in 

 another part of the instructions he is advised to leave both telephones in their 

 places when not corresponding, and in any case to leave the one on the 



