330 KENNELLY-NABESHIMA— ESTABLISHING A 



normally outgoing current is represented as leading, by 30°, the 

 associated outgoing wave e of e.m.f . ; so that at an instant of zero 

 e.m.f., the strength of the current will be 0.5 ampere. In Fig. 2&, 

 the switch at the generator end of the line is supposed to be closed 

 at an instant of zero e.m.f. The instantaneous outgoing current 

 must also be zero at that moment. The first outgoing half wave of 

 current is therefore distorted from the sinusoidal form, and follows 

 a course such as is indicated approximately by the dotted line abc. 

 This distortion gives rise to a splash transient. 



A splash wave transient may therefore be defined as that tran- 

 sient wave disturbance which is due either to closing the line switch 

 at a moment when the generator e.m.f. is off zero; or, if the 

 generator e.m.f. is zero, to the zero of line current forced at that 

 instant, when the surge impedance of the line calls for a definite 

 phase difference between outgoing current and voltage. In general, 

 the splash transient will be greater, the greater the value of the 

 impressed e.m.f. at switch closure. The splash can only be zero 

 in the case of a distortionless line closed at an instant of zero e.m.f. 

 It may, however, be expected to be a minimum, on any ordinary 

 line, when closed at or near an instant of zero e.m.f. ; because if there 

 is no e.m.f. splash, the current splash is usually very small. 



Lumpy Artificial Line Closed at Zero E.M.F. Lumpiness Tran- 

 sients. — If an artificial line, made up of alternate coils and con- 

 densers, is used in place of a smooth and uniform line ; the lumpi- 

 ness of the line will give rise to another type of transient,* which 

 may be called a " lumpiness " transient. This lumpiness transient 

 may be regarded as being produced by oscillatory disturbances 

 between the successive coils and condensers. Lumpiness transients 

 are magnified by the sudden application of a large e.m.f. In other 

 words, the conditions which produce splash transients on smooth 

 lines are also those which favor lumpiness transients on artificial 

 lines. In laboratory measurements of lumpy artificial lines, lumpi- 

 ness transients must therefore be expected over and above the 

 transients due to splash. 



Table I. presents a provisional classification of transients con- 



* Bibliography 37. 



