342 Dr. A. Schuster's Experiments on Electrical Vibrations. 



strength of the electrical vibrations. The following Table shows 

 that the difference in the first deflection which is observed ac- 

 cording as the magnet rotates or not, is sensibly proportional to 

 the strength of the permanent current. The first column gives 

 the first deflection observed when the magnet was not rotating ; 

 the second column gives the difference in the deflection when 

 the magnet rotated ; and the third column gives the ratio of the 

 numbers given in the first two columns. The numbers given in 

 the third column are as nearly constant as could be expected. 

 The chief error of observation is caused by the difficulty of keeping 

 the rotation of the magnet constant for a sufficient length of 

 time. 



First deflection 



Difference in the 



Ratio. 



(magnet quiet). 



first deflection. 



336 



186 



0-055 



285 



161 



056 



230 



11-4 



0-050 



168 



9-8 



0-052 



143 



M 



0-050 



67 



4-1 



0-0G1 



3. By altering the resistance of the wire b Gr I a and that of the 

 wire a b at the same time, we can alter the strength of the elec- 

 trical vibrations, without altering the strength of the permanent 

 current produced by the electromotive force E. The following 

 Table shows that the effect decreases very rapidly as the strength 

 of the electrical vibrations decreases. The first column gives 

 the resistance R introduced into the circuit b G I a \ the second 

 column gives the ratio n of the difference in the first deflection 

 observed according as the magnet rotated or did not rotate, to 

 the first deflection observed when the magnet was quiet.' 



R. 



n. 



2000 



1000 



500 







0-018 

 0018 

 0030 

 0-046 



4. Another series of experiments was made with a galvano- 

 meter the resistance of which was only a itvf units. The first 

 deflection produced by the electromotive force in E was about 

 the same as had been observed with the other galvanometer, 

 because, although the delicacy of the galvanometer was much 

 smaller, a greater part of the current passed through the galva- 

 nometer, the resistance b I Gr a being now a great deal smaller 



