a Conductor the Measure of the Current passing. 357 



These experiments seem to indicate that these lamps 

 might serve very usefully for measuring alternating currents 

 from 50 up to a few hundred milliamperes, or even a thousand, 

 but would not be instruments of much precision. The reason 

 for the discrepancies was not then apparent. 



9, Curves of three lamps of the same manufacture, taken 

 to see how far they followed the same form, are given in 



Fig. 3. 



60 



30 



20 



\ V 

















































-^ 





V 













r~ 

 > 



~0 





\ 













m 



CO 























































OHM 



S 







\\« 



132 134 136 



140 



152 



164 



fig. 3, which indicates that possibly one formula connecting- 

 current and resistance might be employed for all lamps of 

 one method of manufacture. 



10. A platinum-foil ligament in a circular box, exhausted 

 by a Fleuss pump, was then tried. The form of the ligament 



