362 Patterson and Arnold — Electrical Oscillations* etc 



of S' and C had a product LC equal to that of the circuit P', C, 

 B the time of oscillation in the two circuits would be the same : 

 but since the products LC and I/C in the two currents are 

 quite different — the values of t are also different. The photo- 

 graphic study of the sparks bore out the truth of theoretical 

 deductions and showed conclusively that electrical oscillations in 

 a primary current in general do not give rise to a higher number 

 of oscillations in a secondary circuit. If a higher number of oscil- 

 lations occur in a secondary circuit than exist in a primary, 

 there must be an air gap in this secondary circuit and a suit- 

 able arrangement of condensers and self induction. The 

 oscillations which surge across such an air gap in the secondary 

 in general have no relation to the oscillations across their gap 

 in the primary circuit unless the circuits are in resonance. 

 Our conclusion on this point is therefore this : the pilot spark 

 of a primary circuit can give a series of impulses in a second- 

 ary — an increase of electromotive may result — which can 

 force a spark across an air gap in this secondary. The oscilla- 

 tions however of this last mentioned spark are not determined 

 in general by the oscillations of the spark in the primary, and 

 are dependent upon the arrangement of self induction and 

 capacity in the secondary circuit. 



In the course of our experiments to test the question of in- 

 creasing the frequency of electrical oscillations we were led to 

 examine the function of the magnetic field and the air blast 

 in the transformation of electrical impulses. When the spark 

 B, figures 1 and 2, occurs in a strong magnetic field and there 

 are no condensers in the circuit it is instantly blown out with a 

 sharp report. With comparatively small capacity connected 

 with the spark terminals a torrent of sparks leap between the 

 spark terminals. Without the magnetic field these sparks fill 

 a globular space between the terminals. When the magnetic 

 field is made, this spherical space is transformed into a plane of 

 sparks, showing in a striking manner the Amperian law of 

 repulsion and attraction of currents. The amount of light 

 emitted by the passage of the sparks is also greatly increased 

 by the passage of the sparks in the magnetic field ; and it is 

 interesting to observe the breaking away, so to speak, of the 

 sparks from the surfaces of the terminals far from the actual 

 points. The increase of light is doubtless due to the blowing 

 out of the unidirectional fuzzy spark which if it is not blown 

 out acts like a voltaic arc and prevents the condensers from 

 becoming fully charged. When the condenser surface is 

 increased to the proper limit, sparks of larger body take the 

 place of the thread-like sparks, and the spreading out into a 

 plane is no longer observed. Professor Boys from certain eye 

 observations has concluded that a strong magnetic field has no 

 effect upon the oscillations of a spark. We have tested this point 

 by taking photographs of an oscillating spark both in and out 



