328 Mr. R. Sabine on Measuring the Contour of 



Table (continued). 



Interval of time 



Excursion of galvanometer- 



by disk. 





needle. 



0'25 second 





75 divisions. 



0-30 „ 





80 „ 



0-35 „ 





83 „ 



0-40 „ 





84 „ 



0-45 „ 





85 „ 



ential of the battery 



was 



represented by 208 



sions ; the potential of position of point c, or the maximum 

 excursion (after 1 minute) was 99 divisions. Therefore after 

 Y^q of a second the point c had attained 1 per cent, of the po- 

 tential due to its position, and after ^ second 75 per cent. 



By plotting out these values, taking the time and the excur- 

 sions as coordinates of a curve, the contour of the wave is ob- 

 tained. 



Exp. 2. — 308 knots of coiled cable between a and c, b c 

 being a resistance-coil of 3000 ohms. Two batteries (con- 

 nected as in fig. 2), B and B', each ten Minotto cells. 



Excursion of galvanometer- 

 needle. 

 — 50 divisions. 

 -29 „ 

 + 10 „ 

 39 „ 

 57 „ 

 67 „ 

 73 „ 

 78 „ 

 80 „ 

 82 „ 



Plotted out, this curve shows that the neutral point passed 

 c 0*085 second after reversal of the battery at a. 



Exp. 3. — Between a and c, a coiled cable 114 knots ; between 

 b and c, a resistance-coil of 1000 ohms. Two batteries as before. 



Interval by disk. 



0-01 t 



second 



0-05 



?? 



o-io 



j? 



0-15 



j? 



0-20 



j? 



0-25 



j? 



0-30 



?) 



0-35 



?j 



0-40 



jj 



0-45 



?? 



Interval by disk. 





_Cj3 



.cursion oi gaivai 

 needle. 



0-005 second . . . - 



0-006 „ 







-106 „ 



0-007 „ 







- 70 „ 



0-008 „ 







- 38 



0-009 „ 







» 



0-010 „ 







+ 47 



0-011 „ 







85 



0-012 „ 







117 



0-013 „ 







168 ;, 



ons. 



