210 D. W. Shea — Calibration of an Electrometer. 



n. 



Resistance be- 

 tween point on 

 coils to ground 

 and point to 

 quadrants in 

 degrees. 



1000 

 2000 

 3000 

 5000 

 7000 

 8000 

 9000 



Charge 



of 



quadrants in 



volts. 



0-55 

 1-10 

 1-65 

 2-75 



3-85 

 4-40 

 4-95 



Temperature 18° C. 

 Scale readings in cm. 



2-30 



4-61 



6-87 



11-41 



14-98 

 18-21 

 20-50 



2-33 

 4-65 

 6-97 

 11-61 

 15-20 

 18-49 

 20-73 



Mean Deflection 



of of 



the two the needle in 



scale readings. degrees. 



2-315 

 4-63 

 6-92 

 11-51 

 15-09 

 18-35 

 20-615 



0°31'-5 



1 3 

 34 

 36-5 

 25 



37-5 



Charge of Needle, 200 volts. 

 Temperature 17° C. 



1000- 



0-46 



2-00 



1-99 



1-995 



0°27' 



2000- 



0-92 



3-99 



3-99 



399 



54 



3000- 



1-38 



5-99 



596 



5-975 



1 22-5 



5000- 



2-30 



9-98 



9-94 



9-96 



2 15-5 



7000- 



3-22 



14-00 



1396 



13-98 



3 10 



8000- 



3-68 



16-02 



15-96 



15-99 



3 37 



9000- 



4-14 



18-00 



1796 



17-98 



4 3-5 



oooo- 



4-60 



20-00 



19-90 



19-95 



4 30 



It was found that the curve of calibration, when the charge 

 of the needle was 200 volts, was practically constant for a 

 range of temperature from 6° to 25° C. 



The curves of calibration for the cases where the needle has 

 charge of 10 and 20 volts were not examined very carefully, 

 but it was observed that the variation was much greater than 

 in the other cases. The following tables will serve to show the 

 form of the curves for these cases : 



Charge of Needle, 10 volts. 



Resistance be- 

 tween point to 

 ground and 



point to 



quadrants in 



ohms. 



1000 

 2000 

 3000 

 5000 

 7000 

 8000 

 9000 

 10000 



Charge 



of 



quadrants in 



volts. 



4-3 

 9-6 

 12-9 

 21-5 

 301 

 34-4 

 38-7 

 43-0 



Temperature 18° C. 

 Scale readings in cm 



PS 



1-02 



2-24 



3-69 



7-41 



11-83 



14-25 



17-21 



20-25 





Mean 



of 



two scale 



readings. 



Deflection 



of 

 needle in 

 degrees. 



1-04 



1-03 



0°15' 



2-24 



2-24 



30-5 



3-71 



3-70 



51 



7-39 



7-40 



1 41 



11-81 



11-82 



2 41 



14-27 



1426 



3 13-5 



17-16 



17-185 



3 53 



20-26 



20-255 



4 34-5 



