402 



Dr. W. L. Robb on Oscillations 



An inspection of Tables VI. and VII., and of the graphical 

 representation of these observations given in diagram 4, shows 

 that the variations in the charge are increased when the 

 electromotive force of the battery used in charging the con- 

 denser is increased. 



4. Effect of varying the Self-induction. 



In order to determine the effect of varying the self-induction 

 in the charging circuit two sets of observations were made. 

 In the first set, No. 7 B.W.G. copper wire was used in making 

 the circuit, and the total length of copper wire used was 

 50 centim. In the second set an additional piece of copper 

 wire, of the same diameter and 120 centim. in length, was 

 included in the circuit, making the total length of copper 

 wire 170 centim. In this way the self-induction was increased 

 without appreciably altering the resistance. Tables VIII. and 

 IX. give the results of these observations. 



Table VIII. (See also diagram 5.) 

 Mica Condenser (normal charge = 1*971 microcoulombs) 



Observation 

 number. 



Smaller Sell 



'-induction. 



Larger Sell 



-induction. 



Charge of 



Deviation 



Charge of 



Deviation 



Condenser. 



from the 



Condenser. 



from (lie 





Micro- 



normal 



Micro- 



normal 





coulombs. 



charge. 



coulombs. 



charge. 



1 



1-980 



+0-C09 



1-754 



-0-217 



9 



1-968 



-0 003 



2 040 



+0-009 



3 



1 982 



+0-011 



1-904 



- 00U7 



4 



1-969 



-0-002 



1-782 



-0189 



5 



1-958 



-0013 



1-745 



-0-220 



6 



1-968 



-0013 



1-853 



-0-118 



7 



1-91)6 



-0 015 



1-880 



-0 091 



8 



2-008 



+0-037 



1-855 



-0-110 



9 



1978 



4 0-007 



1055 



-0 316 



10 



] -950 



-0-021 



1834 



-0137 



11 



1-952 



-0019 



1 829 



-0-142 



12 



1-968 



-0-003 



1731 



-0240 



13 



1974 



+0-003 



1-723 



-0-248 



14 



1-958 



-0-013 



1-971 



+0-000 



15 



1-950 



-0021 



1-920 



-0-051 



16 



1 967 



-0004 



1813 



-0-158 



17 



2010 



+ 0-039 



1-871 



-0 100 



18 



2-008 



+0O37 



L-900 



-0-071 i 



1 ( .) 



1940 



-0 031 



T771 



-0-200 



20 



1-972 



+0-001 



1-943 



-0 028 



