INDEX 



Arruracy and precision, 593 

 Accuracy, percentage of for watt- 

 hour meters, defined, 493 

 Ageing of magnets, artificial, 34 

 Agnew, P. G. 



tubular electrodynamometer for 



large currents, 87 

 comparison method of testing 

 instrument transformers, 588 

 Alternating current, measuring large, 



86 



Aluminum, conductivity of, 232 

 Ammeter, 54 



inclined coil, General Electric, 71 

 induction, Westinghouse, 449 

 moving coil, 55 



Weston, 55 

 soft iron, Weston, 71 

 thermo, hot wire, 58 

 high frequency, 61 

 parallel wire, 63 

 Anderson bridge, 403 

 Astatic electrodynamometer, 83 

 Astatic needle system for Thomson 



galvanometer, 8 

 Ayrton and Mather universal 



shunt, 52 

 Ayrton and Perry inductor, 344 



H 



Balance, current, 89 



Kelvin or Thomson balance, 92 

 Rayleigh absolute balance, 90 

 advantages of for absolute 

 measurements, 91 



BALLISTIC GALVANOMETER 

 Chapter II, 99 

 calibration of, 103 

 checking device for, 102 

 damped, 109 



critically damped, 120 

 description of, 99 

 movable systems for, 101 

 reading, precautions in, 102 

 shunts used with, 122 



universal shunt, advantage 

 for open circuit work, 



124 

 theory of, 



damped instrument, 



when e.m.f. applied to 

 circuit is a function of 

 time, 109 



when discharge is in- 

 stantaneous (Equa- 

 tion 20), 115 

 when discharge is pro- 

 longed 



according to exponen- 

 tial law, 117 

 according to graph 

 connecting e.m.f. and 

 time, 119 

 by impulses, 118 

 critically damped instru- 

 ment, instantaneous 

 discharge, 121 

 undamped moving coil in- 

 strument, 107 

 undamped Kelvin instru- 

 ment, 109 



Best resistance for Thomson gal- 

 vanometer, 17 

 Blavier test, 673 



707 



