410 BELL SYSTEM TECHNICAL JOURNAL 



operation and maintenance carefully watched during the coming summer. 

 It is hoped that the data obtained in this way will afford sufficient informa- 

 tion to enable us to so modify our present protective practice as to afford 

 adequate protection in all cases, with a reasonable amount of maintenance 

 on the protectors. 



APPENDIX II 



Memorandum from Dr. Jewett to Mr. Warren: 



December 22, 1906. 

 I have enumerated below under a number of different more or less general 

 headings the most important things upon which we have been engaged 

 during the past year. Subjects marked with an asterisk (*) are those upon 

 which work is still being done although in most cases one or more reports 

 have been filed on certain phases of the investigation. 



Cables. 



*1. Work in connection with Conference Case ^23-A on the develop- 

 ment of cable for loading. 

 *2. A design of a switchboard cable for ^ 2 Private Branch Exchanges. 

 3. A study of wool insulated cable for switchboard use. 



Coils. 



*1. A general study of iron for retardation and repeating coil cores. 



2. The development of coils for use in a new form of Private Branch 

 Exchange circuit. 



3. Thorough investigation of the efficiency of repeating coil T-602 

 (25-K) for use as a terminal transformer on loaded lines. 



4. The development of a method for manufacturing balanced phantom 

 repeating coils. 



*5. The development of a shellac insulation for loading coil core wires. 

 *6. The development of a submarine loading coil. 

 *7. The re-designing of an aerial loading coil. 

 *8. The development of extra Hght loading coils. 

 9. The development of a compensating coil for use on telephone lines 

 exposed to alternating current railway induction. 



Condensers. 



1. A study of the alternating current capacity and conductance of ^21 

 type condensers. 



