CONTENTS 



PAUE 

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niAiTKU I 



THK Mh\-l HI.MKNT <>F < 1 



Classes of Instruments (i.\i.\ A.MKMKTKKS -The Tangent Gal- 

 vanometer The Helmholt/ ( lalvanometer The Thomson or 

 Kelvin RehYctinir dalvanon- -netic Shields The Needle 



ten Damping--- Arrangement of the Galvanometer Coils 

 Galvanometer C Cross-section Graded 



Coils Delation between the ( lal variometer Constant and the 

 Resistance of a Thomson (lalvanometer The Beat Resistance for 

 a Thom>.,n (ialvan.-meter The Sensitiveness of Reflecting Gal- 

 neters -. \m|>ere Sen-it Sensitivity Rela- 



tion hetur.-n Time, of Vibrat ion and Current Sensitivity- Normal 

 , .It S-iiMtivity. Microvolt Sensitivity Me^.hm 

 :ty -Design for a rig Galvanometer The Broca 



Galvanometer THE MOTION or THE SUSIKM i F:M 



or A ( i \i.\ \\OMETER The KquatiiMi of Motion Nonoscil- 

 latory Deflection Oscillatory Deflection Logarithmic Decre- 

 ment Influence ,,f Damping on the Tnm- of \'i!>ration Crit- 



! Dampnm HM I).\r>onval or Moviim-eoil ( ialvanome- 



Impurities in the < '.il 



Suspensions EfT- Changes of Tern jx-rature Magnetic 



Damping The Critic -ally Dam; ! ( lulvanometer 



Current and Voltage pension for the Field lie- 



quired to Produce Critical Damping Auxiliary Damping Pos- 

 sible Adjustments The Kinthoven or String Galvanometer The 



Dilddell ThermO-galvanometer POINTS TO BE CONMI' 



\MII KCTINO METER Sc'ii-itivity Period- 



Damping Resistance Freedom from I .f Mechanical 



rlances FYeedom from Stray-Held Kflfects Definiteness 

 of Zero Reading Law of Deflection Visibility of Suspended 

 ^Accessibility for Repairs Temperature Effects Opt i. -a I 

 THE JULIUS DEVICE FOR ELIMINATING THE EFFECTS OF 

 BAMIGAL DISTURBANCES ON GALVANOMETERS SHUNTS The 

 n-Mather I'niversal Shunt AMMETERS Moving-coil Am- 

 DMten WmtoOU S'-mdard Portable Ammeter Therrno-ammetors 

 Duddell 'rhenno-amiii' . h-fre(juency Ammeters 



ilel-uire Ammeter The Use of Hih Resistant ^ IT8I 

 I'tilization of the U'hole If. at rr.xluction Srtionalized 

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