I. Stationary Contacts.- § 1. Introduction. A simplified summary of the theory of stationary electric contacts.- § 2. The contact surface.- § 3. The contact resistance. General theory.- § 4. Calculation of constriction resistances with constant resistivity ? in an isotropic material.- § 5. Constriction resistances when conditions deviate from those in § 4, but with ? still a constant.- § 6. Introduction to thin films on contacts. Contact cleaning.- § 7. The load bearing contact area as a function of load and elastic and plastic properties of the members.- § 8. The relation between contact load and resistance, particularly at moderate and high load.- § 9. Contact resistance on freshly cleaned rods in air at very small contact loads.- § 10. The inductance of a current constriction. Skin effect.- § 11. Electrodynamic repulsion in a symmetric contact of non-magnetic material.- § 12. The capacitance of a contact. Electrostatic attraction in a contact.- § 13. The relationship between electric potential and temperature in a current constriction which is symmetric with respect to the contact surface; that is, the ??-relation.- § 14. The ??-relation in cases of dissymmetry.- § 15. Influence of a thin film in the contact on the ??-relation. Kohler effect.- § 16. The influence of the Joule heat on constriction resistences in symmetric contacts.- § 17. Distribution of the temperature in a symmetric constriction with circular contact surface at given current.- § 18. The (equilibrium) temperature distribution in the constriction of a contact between two metals with different conductivities, both obeying Wiedemann-Franz law. Thermoelectric effects.- § 19. Temperature distribution in the constriction of a contact between members of very different conductivities.- § 20. Resistance-voltage characteristics of clean symmetric contacts. Softening and melting voltages.- § 21. Development of the temperature in a metallic current constriction.- § 22. Growth of films on metals used for contacts, near room temperature.- § 23. Growth of visible oxide films on metals at moderate to high temperature Decomposition at still higher temperature.- § 24. Water film, local cells and rusting.- § 25. Alien solidified films on contacts.- § 26. Tunnel effect.- § 27. Fritting of tarnish films.- § 28. Adherence in dry contacts which are not heated to any influential extent by the current.- § 29. Adherence in contacts that are heated by the current passing through them. Resistance welding.- § 30. About stationary contacts in practice.- § 31. Dimensioning a contact with respect to its heating.- § 32. Contact effects in carbon granular microphones.- § 33. Contact with semiconductors. Rectification. Static electrification.- § 34. Carbon-pile rheostats. Electric resistance of pressed metal powders..- II Thermal Contacts.- § 35. Thermal metallic contacts.- III Sliding, Contacts.- § 36. Survey of fundamentals.- § 37. Sliding contacts in air.- § 38. Boundary lubrication.- § 39. Theory of friction and wear of carbon contacts. Lubrication by means of solid lubricants as graphite and molybdenum disulfide.- § 40. Stick-slip motion. The temperature in currentless sliding contacts.- § 41. Frictional wear in metallic contacts without current.- § 42. Electrical performance of carbon brushes on rings and commutators when arcing is excluded..- § 43. The temperature in the sliding contact between a carbon brush and a copper ring or commutator.- § 44. Friction and wear with a carbon-brush collector contact.- § 45. Theory of commutation with special regard to voltage flashes and arcs.- § 46. Current collectors for trolley cars.- § 47. Electric noise in contacts.- IV Electric Phenomena in Switching Contacts.- § 48. Introduction.- § 49. Ignition of arcs in switches.- § 50. VI-characteristics of the stationary arc in air; their use for calculation of the duration of drawn short arcs.- § 51. Vacuum arc; particularly its extinction.- § 52. Interrupting an a.c. current.- § 53. Breaking direct current.- § 54. Electric oscillations generated by d.c. arcs.- § 55. Bouncing.- § 56. Material transfer in switching contacts. A survey.- § 57. Discharge transients.- §58. Are duration during contact closure with voltages below 200 to 300 V.- § 59. Floating.- § 60. Arc duration on breaking contact without quenching. Circumstances common to Communication Engineering.- § 61. Quenching a drawn arc by means of a capacitor, parallel to the contact.- § 62. Capacitive quenching when an arc with a very small duration or no arc is drawn.- § 63. Quenching of arcs by a resistance parallel to the operating contact or to the inductive coil.- § 64. Details about the types of arc in relay contacts and the material transfer produced by them.- § 65. Bridge transfer and short are transfer at contact separation.- § 66. Theory of the bridge transfer.- § 67. Bridge material transfer in the shape of pips and spires.- § 68. Mercury switches.- § 69. Application of statistics to contact operations.- § 70. The choice of contact material; contact shape for practical applications.- Appendices.- § I. Elasticity, plasticity and hardness.- A. Introduction.- C. Plastic deformations. Dislocations.- D. Mathematics of plastic yielding.- E. Indentation in an isotropic semi-infinite body, produced by a spherical indenter (ball).- F. The ball and pyramid indentation tests. Hardness.- G. Influence of friction on the indentation.- H. Diffusion effects.- I. The work consumed by a plastic deformation. Examples.- § II. Electronic conduction in solids.- A. Introduction.- B. General concepts concerning conduction.- C. Quantization of the electrons in a crystal and the constitution of a band.- D. Influence of the temperature on the distribution (or partition) of electrons on cells in metals.- E. Current carriers in semiconductors.- F. Mobility of current carriers. Resistance.- G. Surface potential barrier of a metal. Thermionic emission of electrons.- I. Metal-semiconductor contact.- A. Heat capacity.- B. Thermal conduction.- § IV. Probability. Noise.- A. Normal distribution.- B. Probability paper.- D. Electrical noise.- § V. Structure, electrical and thermal conductivity of carbons 404 A. Introduction. Graphite lattice.- B. Carbon grades. 406 C. Graphitization.- D. Electrical conductivity of carbons.- E. Heat conductivity of carbons.- § VI. Hydrodynamic or thick film lubrication.- § VII. Metal whiskers 417 A. Whiskers formed from the solid metal.- B. Whiskers rapidly formed from metal vapor.- C. Mechanical and magnetic properties of whiskers.- D. Metallic dendrites in semiconductors.- § VIII. Some fundamental formulas concerning electric discharges.- A. Introduction. Kinetic fundamentals.- B. Drift velocity.- D. Plasma.- E. Current in vacuum restricted by the space charge of the current carriers.- § IX. Theory of the electric arc.- A. Introduction.- B. Cathode layer.- C. Emission of primary electrons from the cathode.- D. The ion current in the cathode layer.- F. Summary of the results presented in Table (IX,5).- G. Power balance at the cathode.- H. Power balance at the anode.- I. Voltage-current characteristics of arcs.- J. Pinch effect.- § X. Tables.- § XI. Diagram XI in two copies, one detachable.- Author and literature index.- Errata.