﻿768 Dr. A. Sellerio on the Repulsive Effect upon 



As my arrangement was a very similar one, I can adopt 

 without committing (especially with small currents) a con- 

 siderable error, the same value of E, and according to 

 (l')-(2), the correction (V + E) becomes 



-0-296 1-0-03 1 2 for the anode 



+ 0-296 1-0-03 1 2 for the cath 



le? } . (3') 

 ode. J 



3. In my experiments almost all the readings were taken 

 by keeping the arc length L constant and varying the 

 current. But, having observed that the carbon quality has 

 a far greater influence than L on the results *, it would be 

 useless to relate here the individual series of measurements. 

 In Table I. I have therefore recorded only the mean 

 values of P upon anode and upon cathode for arc length 

 L = K4mm., by a given current, as they result from the 

 whole of my readings after the corrections (3'). 



Table I. 



Anode. Cathode. 



Current Deflexion F P + Deflexiou F P_ 



aul P- a. dyne. dyne. a. dyne. dyne. 



3 36 1-30 0-14 



4 62 2-23 0-57 



5 88 316 0-93 



6 114 4-10 1-24 



7 140 504 1-49 



8 166 5-90 1-61 



9 204 7-35 2-26 



10 240 8-65 2-69 



11 290 10-4 3-49 16 0-58 0'29 



12 336 12-1 4-23 48 173 0-96 



13 380 13-7 4-77 80 2-87 1-66 



14 436 15-7 5-68 112 4-03 2-31 



15 480 173 6-07 144 5-19 2-87 



16 540 19-4 6-97 176 635 3-38 



17 600 21-6 7-88 210 7"55 3"87 



18 ... ... 260 9-35 4-95 



19 ... ... 318 11-50 6-35 



20 ... ••• 376 13-60 7"42 



4. Comparing Table I. with Duffield's results, we shall 

 see, in spite of several numerical discrepancies, a good agree- 

 ment in the general behaviour of the observed effect. So 

 far as concerns the mean value (i(P+ + P-), which is 



* When the carbon rods are very close together (L=r->0), the repul- 

 sions P + and P_ become evidently greater. 



