230 BELL SYSTEM TECHNICAL JOURNAL 



Having gone this far in the laboratory, it was decided to bring the 

 results of our investigations to the attention of one of the cable 

 operating companies with the object of securing a practical trial of a 

 permalloy-loaded ocean cable. 



On being shown what could be accomplished with permalloy loading, 

 the Western Union Telegraph Company was quick to take advantage 

 of this means of extending its cable facilities, and shortly thereafter 

 arrangements were made whereby the Telegraph, Construction & 

 Maintenance Company, Ltd., was to manufacture a cable for the 

 Western Union Telegraph Company, using permalloy loading material 

 supplied by the Western Electric Company and applied and treated 

 under the direction of Western Electric engineers. 



As a part of this undertaking, it was decided that prior to laying a 

 complete transoceanic length of cable it would be desirable to make, lay 

 and test a shorter length in order to obtain experience in manufacture 

 and a test of its mechanical and electrical properties after it had suffered 

 the extreme treatment to which a deep-sea cable is subject in laying. 

 Accordingly, for such an experiment, 120 miles of cable of the same type 

 which it was proposed to use for a transoceanic length was laid in a 

 loop from the south shore of Bermuda in October 1923. Very thor- 

 ough tests were made jointly by Western Electric and Western Union 

 engineers to determine whether the electrical characteristics had been af- 

 fected by laying and what attenuation and distortion were actually pro- 

 duced by such a cable. The results obtained were in excellent agree- 

 ment with our predictions, and accordingly manufacture of the full 2300 

 miles required to connect New York and Horta was at once under- 

 taken. 



The New York-Horta cable which, like the 120-mile trial cable, 

 was manufactured by the Telegraph, Construction & Maintenance 

 Company with permalloy loading material applied and treated under 

 the technical direction of Western Electric engineers, was laid in 

 September 1924. Within an hour after the cable had been turned 

 over to our engineers for test, a speed of 1500 letters per minute was 

 obtained with the terminal apparatus which had been designed and 

 provided in advance. In this case the messages were received on a 

 high-speed siphon recorder of special design. Shortly thereafter, with 

 the same apparatus, a speed of over 1900 letters per minute was 

 obtained. 



The speed of the cable having been demonstrated, commercial 

 operation was quickly established with temporary operating equip- 

 ment utilizing siphon recorders in conjunction with vacuum tube 

 amplifiers. This type of operation was continued for about two 



