SUBMARINE TELEGRAPH CABLES 



437 



work shelves provide space for mounting the tubes and heavy 

 apparatus such as coils and coupling condensers. The tube of the 

 first stage is held in a spring suspended socket, damped by an oil 

 dashpot.^* The socket of the second stage tube is sufficiently pro- 

 tected from vibration by a sponge rubber mounting, while the sockets 

 of the third and fourth stages need no special protection. Dry cell 

 grid batteries are mounted on the lower shelf of the framework. 

 The numerous external connections are brought to the terminal strip 

 which may be seen along the lower part of the back of the framework. 

 The panel assembly is mounted in the upper part of a mahogany case, 

 lined with copper. The lower part of the case contains the shaping 



Fig. 4. 



networks which are connected between the cable and the amplifier 

 All adjustments are made either from the front of the panels or on 

 apparatus contained in the lower part of the cabinet, and as all the 

 elements of the amplifier are inherently stable, when the adjustments 

 for shaping the signal at any given speed have once been determined 

 they may be quickly duplicated at any time. 



The relay control desk combines the apparatus for correcting the 

 signal zero wander with means for adjusting the current through the 

 relays used in the multiplex printing telegraph system and includes 

 several switches used in the control of the latter apparatus. 



In designing the amplifier the necessity of maintaining continuous 

 operation and easily and quickly remedying any minor troubles was con- 

 sidered of the utmost importance, and this led to its being made large 

 enough so that work may be done inside of it without having to remove 



1* W. A. Knoop, Patent U. S. No. 1,523,430, January 20, 1925. 



