Potts — Rowland's New Method. 



101 



gives the results for R 2 R 4 nearly constant and R 2 /R 4 varied. 

 The variation in R 2 /R 4 was about 200 per cent and A/T is 

 practically constant. The slight increase of A/T in the last 

 two measurements is due to the larger current in arm 1 and a 

 consequent heating of the condenser and also to the fact that 

 after the coil of the electro-dynamometer had been heated 

 slightly, it would be cooled a small amount before its resist- 

 ance could be measured. Table IY shows the results when R A 



R 4 = 1505-8 



Table IY. 

 r = 4810 



Date, 

 etc. 



4-19 1 



118 5 



2 



4 



R 2 



2070' 

 2070- 



1009* 

 1009- 



R 3 



76,600 

 74,200 

 36,120 

 35,970 



Ri 



34-68 

 34-80 

 34-76 



34-80 



Calculated. 



40-70 

 42-02 



42-07 

 42-25 



(R'i-Ri) X 

 •0312 6-02 192-9 ) 

 •0367 7-22 196-7 j" 

 •0375 7'31 194-9 } 

 ■0378 7-45 197-1 f 



Mean. 

 194-8 



196-0 



99-48 3,542 34"75 42*30 -0386 7'55 195*6 195*6 



is kept constant and R„ and R 3 are varied. These also show 

 A/T constant. It appears then from the above facts that A 

 is a quantity independent of the relative values of the resist- 

 ances in the different branches of the bridge. 



In the next test the period was kept constant and the electro- 

 motive force acting on the condenser was varied about 300 per 

 cent. The results of this test are given in Table Y. The 

 values for the higher electromotive forces are slightly greater, 

 owing to the two heating effects mentioned above. Aside from 











Table V 

























Yolts e.m.f. 





R 2 = 1008-9 



R 4 = 



= 303-8 







: 



acting on 











Calculated 







A 



condenser 



Date, 



R 3 



r 



Ri 



R'i 



A 



T 



=7 



etc. 











R i — Rj 





~t" 





3-10-99 

















1 

 27 



2 



6649 



24,410 



35-45 



46*14 



10-69 



•0523 



204-3 



240* 



6593 



24,410 



35-34 



46*53 



11*19 



•0562 



199-3 



240* 



3 



6797 



12,490 



35-13 



45*17 



10*04 



•0508 



197-6 



152* 



4 



6777 



12,490 



35-15 



45.31 



10*16 



•0511 



198*9 



152* 



5 



6606 



6,348 



35-03 



46-56 



11*53 



•0584 



197*3 



77* 



6 



3-14 



6 



28 



7 



6473 



6,348 



34-96 



47*57 



12*55 



•06418 



195*5 



77* 



6591 



4,807 



34-73 



46*60 



11*87 



•0590 



201*2 



76* 



6803 



6,371 



34*79 



45*14 



10*35 



•0515 



201*1 



142* 



8 



6732 



6,371 



34-78 



45*61 



10*83 



•0540 



200*6 



142- 



9 



6555 



18,830 



35-01 



46*74 



11*73 



•0567 



203*5 



243- 



