xii CLASSIFICATION AND NOTATION. 



/ in some places represents temperature and at another place it 

 may stand for an interval of time. The meanings of these sym- 

 bols are explained every time an equation is discussed in the 

 text, and therefore symbols that are used only once or twice in 

 the text are not given in this table. 



a, j3, (/>, are used for angle ; /3 is also used for temperature 

 coefficient of resistance, and for coefficient of linear 

 expansion. 



c& magnetic flux density. ' 

 C capacity. 

 E t e electromotive force or voltage. 



E a = electromotive force induced in an armature. 

 E x = electromotive force between the terminals ot 

 a dynamo. 



f frequency of an alternating electromotive force or cur- 

 rent in cycles per second. The letter/" is also used 

 for electric field intensity. 



F force ; sometimes used for field loss of a dynamo. 

 $F magnetomotive force. 



H quantity of heat expressed in ergs or joules. 

 h conical intensity of a beam of light in Hefners or in 



candles. 



3{ magnetic field intensity. 

 /, i current. 



7 o = armature current, 7 = shunt field current. 

 7 = series field current, I x = current in external 



. circuit. 



The letter 7 is also used for the sectional intensity of a beam 

 of light, or for intensity of illumination. 

 3 intensity of magnetization. 

 k inductivity of a dielectric. 

 L inductance. 

 / length. 



m magnetic pole strength. 

 IJL magnetic permeability. 



