. 



34 



ELEMENTS OF ELECTRICAL ENGINEERING. 



two actions are fundamentally identical, and the one or the other 

 may be assumed as the basis of the discussion of any given case 

 according to convenience. Thus in discussing the action of the 

 alternator in article 2j the notion of the rate of change of flux is 

 employed, whereas the notion of the cutting of lines of force is em- 

 ployed in the discussion of the direct current dynamo in article 28. 



TABLE OF UNITS.* 

 ELECTRIC. 



MAGNETIC. 



"* Appendix A, on the magnetism of iron, is essentially a continuation of this 

 introductory chapter on elementary theory, and the units of magnetomotive force, 

 reluctance, permeability, etc., are tabulated here for convenience. Names in paren- 

 theses have not yet been adopted by the International Electrical Congress. 



