16 BELL SYSTEM TECHNICAL JOURNAL 



serve as an effective supplement to radio not only between North America 

 and Great Britain but also between North America and all of Europe, with 

 land lines extending the circuits to all important centers of the European 

 continent. It is to be expected, too, that the cable will find important 

 application in other locations than across the north Atlantic. Notably, 

 this type of cable is particularly promising for trans-Mediterranean service. 

 Indeed, the same principles of construction which are proposed for the 

 transatlantic cable may be applied over much shorter distances. With 

 some modification of design, the repeater can be incorporated in lead- 

 covered cables for shallow seas and afford transmission advantages of 

 carrier as well as the economy of broad-band. 



If one tries to imagine the world-wide transoceanic network of the future, 

 he ma"*'" well envisage a net comprising a large number of light link..^ 

 a small number of heavy linkages over the most important routes. The 

 light linkages will represent direct short-wave single-channel or twin- 

 channel connections using relatively small power. The heavy linkages 

 will comprise highly developed powerful broad-band short-wave radio 

 systems making full use of frequency and directional diversity supplemented 

 by broad-band submarine cables and in a few cases by long-wave radio 

 as well. 



From purely physical considerations, it appears feasible to provide all 

 of the facilities for telephone connection between all points on the earth 

 that its inhabitants are likely soon to require. To what extent these 

 facilities will actually be developed will depend on demand and that, to a 

 considerable extent, on cost. It will be interesting to survey briefly this 

 question of prospective demand to see whether after all it promises to be 

 great enough to justify the installation of broad-band cable and radio sys- 

 tems such as are here proposed. 



There are so many factors that contribute to telephone demand that it is 

 impossible to make any very reliable estimate. In addition to cost, there 

 are factors of differences in time, in language and in telephone habits and 

 also the factors of community of interest and speed of service. Similar 

 factors affect the demand for telegraph service, but the transatlantic tele- 

 graph habit has had more time to mature fully and may reflect more accur- 

 ately than the telephone the demand that exists for rapid communication 

 between Europe and America. 



One possible way to estimate what the future may have in store for 

 transatlantic telephony is to compare the flow of telegraph trafiic, say 

 between London and New York, with that between New York and some 

 west-coast American city, and then to examine how intensively telephone 

 service has been developed relative to telegraphy over the two routes. 

 Because of its comparative stability over a period of years, New York- 



