INDEX 



713 



Insulation resistance, insulation re- 

 sistance of commercial circuits 



with power on, 214 

 loss of charge method, 209 

 Megger, Evershed, 213 

 voltmeter method, 208 

 Irwin astatic electrodynamometer, 

 si 



Leeds and Northrup speed regu- 

 lator, 430 



Lincoln synchroscope, 540 



Load boxes for meter testing, 494 



Logarithmic decrement, 30 



Loop tests, 676 



Low resistances, measurement of, 

 190 



Julius suspension, 49 



K 



Kelvin or Thomson balance, 92 

 Kelvin or Thomson double bridge, 



191 



best resistance for Thomson 

 galvanometer, used with, 

 195 



galvanometer current in, 194 

 precision measurements with, 



198 

 Reeves method for adjusting 



ratio arms, 199 

 sensitivity attainable with, 



196 



Wenner method for eliminat- 

 ing lead resistances, 199 

 Kelvin or Thomson galvanometer, 5 

 Kohlrausch 



method of overlapping shunts 

 for resistance measurements 

 using differential galvanom- 

 et< -r, 159 



Lag adjustment for induction watt- 

 hour meters, 475 

 >il for commutating watt-hour 

 meters, 471 



i nd Xorlhrup potentiometer, 

 274 



M 



Magnetic damping for moving coil 



instruments, 38 

 Magnetic shielding, 8, 22 

 Magnetic vane ammeter and volt- 

 meter, 70 

 Magnetic vane frequency meter, 



551 

 Magnets 



ageing of, 34 

 cast iron, 34 



temperature coefficient of, 34 

 Manganin resistance wire, 129 

 Maximum demand indicators, 511 

 Maxwell, J. C. 



absolute measurement of capac- 

 ity, 364 



comparison of inductances, 

 386 



of mutual inductances, 416 

 Megger, Evershed, 213 

 Mercury motor meters, 484 

 ampere-hour meter, 485 

 Ferranti, 485 

 Sangamo, 487 



watt-hour meter, Sangamo, 488 

 Meter testing, 490 



ficticious loads and arrange- 

 ments for phase shifting, 



500 



load boxes, 494 

 methods of testing, 493 

 phase shifting transformer, 



Drysdale, 502 

 portable standard watt-hour 



meters, 495 

 sources of error in meters, 493 



