Electric Strength of Solid Dielectrics. 127 



Table II.— Glass * 

 Frequency 50. A = 1-60 . 10" 6 . B = 2'29 . 10" 10 . A/B = 7000. 



Thickness. 



Breakdown Voltage. 



Diff. per 

 cent. 



Observed. 



Calculated. 



•02 cin. 



•053 



•067 



6,400 

 12,150 

 13,600 



6,380 

 12,000 

 13,800 



-0-25 



-1-2 



+17 



Table III.— Mica f. 

 A=3'3.10" 7 . B = l-0.10- U . A/B: 



33,000. 



Thickness. 



Breakdown Voltage. 



Diff. per 









Observed. 



Calculated. 



cent. 



•001 cm. 



3,400 



2,900* 



-145 



•002 



6,000 



5,600 



-67 



•003 



8,200 



7,700 



-6-0 



•004 



10,000 



9,750 



-2-5 



•005 



11,800 



11,600 



-1-6 



•006 



13,400 



13,400 



00 



007 



15,000 



15,100 



+0-5 



•008 



16,300 



16,700 



-f-3-0 



•009 



17,800 



18,200 



4-2-2 



•010 



19,000 



19,650 



+3-5 



A=7 



Table IV. — Porcelain %. 

 7.10" 6 . B = 3-44.10- n . A/B 



2-24. 10 ; 





Breakdown Voltage. 





Thickness. 





Diff. per 









Observed. 



Calculated. 



cent. 



01 cm. 



13,600 



12,000 



-11-6 



•2 



25,200 



23,200 



-7-8 



•3 



35,200 



33,900 



-50 



•4 



44,300 



43.500 



-1-6 



•5 



53,000 



52,500 



-0-8 



•6 



61,000 



61,000 



00 



•7 



69,000 



69,500 



4-0-06 



•8 



77,000 



77,500 



4-006 



•9 



84,000 



85,500 



4-1-7 



X, 



92,000 



92,000 



00 



There is, therefore, a good agreement except at the lowest 

 values between the observed and calculated voltages. 



* Moscicki, £•. T. Z. 1904, pp. 527, 529. 

 t C P. Steinmetz, loc. cit. 



\ Weicker, loc. cit. 



