ELECTRIC OSCILLATIONS AND ELECTRIC WAVES. 251 



cause a continually increasing zigzag distortion of the chain of 

 ether cells ab, and this zigzag distortion constitutes an electric 

 field at right angles to the magnetic field in Fig. 193, that is to 

 say, a tapering magnetic field produces a continuously increasing 

 electric field at right angles to itself. * 



132. The electric wave. Figure 194 represents an electric 

 wave traveling along a transmission linef in the direction of the 



electric current 



A' 



Fig. 194. 



heavy arrows. The fine vertical lines represent the lines of 

 force of the electric field and the dots represent the lines of force 

 of the magnetic field which is perpendicular to the plane of the 

 paper. The tapering electric field in the front part of the wave 

 causes a continual increase or building up of magnetic field in that 

 part of the wave, the tapering magnetic field in the front part 



* This is a modified form of statement of the law of induced magnetomotive 

 force. It is a verbal statement of the differential equation 



*Y - A **L 

 dt ~ dx 



in which Y is the y-component of electric field and N is the z-component of 

 magnetic field. One form of this differential equation is discussed in Art. 116. 

 t The wires in Fig. 194 are supposed to be broad flat metal ribbons. 



