HIGH-SPEED OCEAN CABLE TELEGRAPHY 251 



on numerous occasions to operate cables with these ampHfiers during 

 the entire course of severe thunder storms with the loss of only an 

 occasional letter due to lightning discharges. 



Apparatus for Automatic Operation 



The first operating tests of the New York-Azores cable were made 

 with the signal-shaping amplifier described in the preceding section. 

 For these tests cable-code operation with a siphon recorder was 

 employed, this type of operation being chosen because it would 



Fig. 8 — High-speed cable-code transmitter 



permit direct comparison of the behavior of the loaded cable with 

 that of ordinary cables. The ordinary cable-code transmitters and 

 siphon recorders were, however, incapable of operation at the predicted 

 speed of over 1500 letters per minute and a new transmitter and 

 recorder had to be provided for testing and demonstrating the operation 

 of the new cable. 



The high-speed transmitter which was developed for these tests is 

 shown in Fig. 8. This transmitter makes use of the ordinary perfo- 

 rated tape used with standard types of cable transmitters but instead 

 of opening and closing contacts by mechanical means it employs 

 pneumatic means for this purpose, the perforated transmitting tape 

 being utilized in the manner of the perforated sheet in a player-piano. 



