LIVING TOEPEDOS IN BERLIN. 495 



in order that the actions at a distance of the inductorium on the 

 galvanometers should disappear. This aim seemed to be sufficiently 

 attained when all the conducting wires were thick and covered with 

 guttapercha. But here also, the opening shocks proved much 

 weaker in their effect on the galvanometer P than the closing 

 shocks, and the difference was so much the greater as the primary 

 coil was pushed into the secondary ; with a certain strength of the 

 induction indeed, the effect of the opening shock disappeared, and 

 beyond that it was reversed, so that the mirror was deflected in the 

 same direction by it as by the closing shocks, only much more 

 feebly and very irregularly. 



I now suspected that sparks sprang over in the galvanometer 

 coil itself, although I did not understand how inverse deflections 

 should result. However, in order to proceed quite surely, I replaced 

 the usual high resistance bobbin of the galvanometer by a similar 

 one wound with wire covered with guttapercha, but the result 

 remained the very same ; afterwards, just as before, the series of 

 opening shocks produced an infinitely small deflection in comparison 

 with that due to the closing shocks, and with a greater strength of 

 induction, the former deflection was inverted, i.e. the opening 

 shocks acted apparently in the same direction as the closing shocks. 

 That the opening induction continued in full force, was proved 

 by sparks at every interruption at any part, and by lateral dis- 

 charges when opportunity offered at any exposed part of the 

 circuit. 



Single closing and opening discharges, produced in the pri- 

 mary circuit by means of a key while the disjunct or remained at 

 rest, effected quite regular deflections equal in amount on both 

 sides of the zero point ; but the most remarkable fact was, 

 that when Wagner's hammer or Foucault's mercury interrupter was 

 put in the primary circuit instead of the disjunctor, the closing 

 and opening shocks maintained equilibrium as perfectly as was ex- 

 pected. 



As the mirror was now observed to vibrate in time with the 

 interruptions, the suspicion arose that the disappearance of the 

 effect produced by the opening discharges on the mirror, might be 

 connected with the greater number of interruptions which occurred 

 in using the disjunctor, owing to its being turned by the water- 

 motor. I therefore directed an assistant to turn the disjunctor 

 first slowly, then more and more quickly by means of the pulley 

 connected with it : this proved that in fact the opening shocks 



