Analytical Study of the Alternating Current Arc, 329 



Table I. B. 



Observations on the Periodic Variation of the Intensity of the 

 Light of an Alternating Current Arc. 



Light from Crater. Short Arc. 



Frequency .....= 83*3-^. 



Length of arc = 0*42 cm. 



Potential-difference (P.D.) of carbons ~) _ _ on il 



(mean square value) J " 



Current (mean square value) . . . . = 14 amperes. 



Power expended in arc = 504 watts. 



Pressure at alternator terminals . . . = 98 volts. 



Angle of 

 Phase. 



Current 

 through Arc 

 (instantaneous 



value). 



P.D. 



of Carbons 



(instantaneous 



value). 



Angle of 

 Phase. 



Intensity of 



Light from 



Crater of 



tower Carbon. 







+16-5 



+42 



12 



60 



20 



+10-2 



+25-3 



33 



34-5 



40 



+ 3-1 



+10-2 



53 



28 



60 



- 11 



-14-2 



74 



31 



80 



- 5-4 



-27-7 



95 



24 



100 



-134 



-32-4 



116 



44 



120 



-187 



-38-4 



137 



71 



140 



-20-4 



-48-9 



157 



101 



160 



-19-8 



-52-3 



178 



148 



180 



-15 



-48-4 



200 



91 



200 



- 8-8 



-31 



205 



93 



220 



- 33 



-11 



226 



61 



240 



+ 1-5 



+11-4 



247 



42 



260 



+ 63 



+26-4 



268 



3L5 



280 



+130 



+34-9 



289 



41 



300 



+18-7 



+39-4 



309 



56 



320 



+21-5 



+44-4 



330 



65 



340 



+21-2 



+45-8 



351 



55 



360 



+165 





119 



163 



160 



-19-8 



-49 







140 



-20-3 



-48 







