792 



INDEX. 



Thomson (Sir W.) effect, 276, 1034; 

 theory of thermoelectricity, 276 ; 

 quadrant electrometer, 799, 810 ; 

 absolute electrometer, 806 ; gal- 

 vanometer, 849; double bridge, 



975- 



Threads, silk, 713. 



Throw of a galvanometer needle, 506. 

 Time, measurement of a very short, 



895. 

 Torsion balance, 415, 706; coefficient 



of, 7HJ determination of, 709; laws 



of, 707 ; method of, of measuring 



currents, 830; methods of, 1142. 

 Torus, magnetisation of a, 411. 

 Tourmaline, electricity by heating, 649, 



1075 ; compression of, 654. 

 Transformers, 1284. 

 Transient currents, 883, 936. 

 Transition, resistance of, 988. 

 Tube, calibration of, 921 ; offeree, 35 ; 



of induction, 115. 



U 



Uniform field, 130, 139. 



Units, ratio of, 1129; electromagnetic, 

 electrostatic and electromagnetic, 461, 

 473 ; electrical, 603 ; fundamental, 

 603; mechanical, 605 



Unlimited wire, 226 



Unpolarizable cells, 262 



VALVE, electrical, 821. 

 Vapours, conductivity of, 1006. 

 Variable state of a conductor, 223. 

 Variation, magnetic, 309; apparatus, 



1183; of the compass, 1231. 

 Varley's machine, 195. 



Velocity, dimensions of unit of, 605 ; 

 of light, 1138. 



Verdet's law, 594; constant, 1296. 



Vernier, 658. 



Vibrations, pendulum, reduced to in- 

 finitely small angles, 691. 



Viscosity, 710. 



Volt, 613. 



Voltaic batteries, work of, 1241. 



Voltameter, 250. 



Volta's straw electrometer, 799 ; dis- 

 covery, 9, 186; law, 188, 272; con- 

 clusions from, 274; couple, 261. 



Von Helmholtz's coil, 746; bridge, 973. 



W 



WATER, resistance of, 1291. 



Watt, 1241. 



Wave, electrical, 230; duration of pro- 

 pagation of, 231; plane, 630; pro- 

 pagation of, 642. 



Weber's theory, 426 ; hypothesis on 

 magnetism, 560 ; tangent galvano- 

 meter, 836, 848, 859. 



Weight, unit of, 656. 



Weights, correction for change of tem- 

 perature in, 651. 



Wheatstone rheostate, 930; bridge, 

 942; coil, 964; wire, 966. 



Wire, fatigue of a, bridge, 965 ; cali- 

 bration of a, 972; unlimited, 226; 

 of finite length, 236. 



Work, of a Holtz machine, 1280 ; 

 available in a current, 1243; elec- 

 trical in displacement, 96; electro- 

 magnetic, 457. 



YIELD of electricity, 825. 



