Electric Waves passing through Telegraph Lines. 329 



Exp. 4. — The same arrangements as in exp. 3, with the ex- 

 ception of the resistance (b c), which was reduced to 500 ohms. 



Excursion of galvanometer- 

 needle. 

 . . —39 divisions. 



Interval by disk. 



0*003 second 

 0-004 „ 

 0-005 „ 

 0-006 „ 



-21 



- 2 

 + 13 



. -122 



?? 



. - 61 



?? 



. + 2 



v 



. + 78 



?? 



. +106 



V 



. +184 



V 



time by an 



increase of the 



The reduction of the end resistance (b c) to half its value, 

 therefore, altered the time of the neutral point passing from 

 0-009 to 0-005 second. 



Exp. 5. — The resistance was increased to 5000 ohms, the 

 other details being the same as in the preceding experiment. 

 Interval by disk. Excursion of ^vanometer- 



0*015 second . . . —182 divisions. 



0-016 „ 



0-017 „ 



0-018 „ 



0-019 „ 



0-020 „ 



0-021 „ 

 This shows an increase of the 

 end resistance. If these end resistances represent the resist- 

 ances offered by the coils of receiving-instruments, the results 

 of the last three experiments confirm our experience that by 

 increasing the instrument-resistance without correspondingly 

 increasing the sensitiveness, we lessen the rate of signalling. 



Fig. 5. 

 a c & b 



By means of two lengths (114 and 190 knots) of coiled 

 cable, I was enabled, in a total length of 304 knots, to put the 

 accumulator in contact with two intermediate points, viz. c (at 

 114 knots from a) and c' (at 190 knots from a). 



Exp. 6. — Accumulator inserted at c (fig. 5) 114 knots from 

 a ; and b directly to earth. Two batteries of five cells each. 



Excursion of galvanometer- 

 needle. 

 — 24 divisions. 



Interval by disk. 



0*032 second 



0-033 „ 



0-034 „ 



0-035 „ 



0-036 „ 



0-037 „ 



0-038 „ 



0-039 „ 



0-040 „ 



-17 

 -12 



- 7 



- 2 

 + 3 



7 

 12 

 20 



