WORLD-WIDE TELEPHONY 501 



As time goes on land lines may become possible for many inter- 

 continental routes where now, because of lack of highways or railways 

 and the wild and unsettled nature of the country, they are out of the 

 question. 



Operating and Commercial Proiuems 



In addition to the technical problems and limitations associated 

 with the development of a world-wide telephone service which are 

 outlined in the foregoing section, there are numerous operating and 

 commercial problems and still other difficulties of a general nature. 



Differences in Time 



Limitations of a fundamental character are imposed by the dif- 

 ferences in time on different parts of the earth's surface. These 

 differences for a number of the principal metropolitan centers of the 

 world are indicated in Fig. 10. If the business day be assumed to be 

 8 hours long, it is evident that as a result of the dififerences in time 

 there is for each city one-third of the earth's surface on which the 

 time is so different from that of the city in question that there is no 

 overlap of the business day. For western Europe this third of the 

 world is for the most part in the Pacific Ocean, so that, as will be 

 noted from Fig. 10, there are few important centers in the world in 

 which the time is more than 8 hours different from that of western 

 Europe. The western part of the Ignited States, however, has time 

 differences of more than 8 hours with a large part of Europe, Asia 

 and Africa. During some portion of the waking day there is an 

 overlap of time between any two points on the earth. 



Language 



Another limitation, though of a less inherent nature, is the difference 

 in language between different nations. There is as yet no evidence 

 that the electrical requirements for satisfactory transmission of speech 

 are substantially different with different languages, but language 

 differences produce a problem in many intercontinental telephone 

 conversations as often one subscriber is using a language of which 

 he is not w^holly master, and this may sometimes apply to both. 

 Under these conditions the transmission requirements of the circuit 

 for a given ease of carrying on con\ersations is unquestionably greater 

 than when the subscribers are conversing in their ngtiv^e tongue. 

 Hence, there is need in the ultimate development of intercontinental 

 telephone systems for a high standard of transmission. 



Language differences also complicate the operating problem, as it is 

 important that the operators understand each other easilv. This is 



