( 319 ) 



of \]\r slriiiu,- in llio liiiiiliiiii- case in (|ii('slioii'). V\'^s 4, 5 and (> of 

 the plalo were (akcn willi llio same siriiii;' as (lie Ibrnier li^L»iires. 

 For tlie ('oniiectioiis we i-cfor l<» tig-nrc 2 in llie le\(. The dovialion 

 is now 30 mm. Again 1 mm. of absciss is 0.0Ü2 sec. and 1 mm. 

 of ordinate =: '2 X 10 ' Amp. 



R = 1300 Ohms. 



n = 27 „ 



IT/ =: (SGOO ,, , from whicli we raU*nh\le 



Ii;— J327 and >r' = 1148 Olims. 



Tn tig, 4 liie capacity of the conden.sei- = 0, hence 7'=0. 

 ,, ,, 5 „ ,, ,, ,, ,, =z 0,G,u/., „ 7'=:O,09fj. 



„ „ 6 „ „ „ „ „ = 0,7^,/'., „ r=0,80(7. 



One sees that the oscillatory motion, the period of which is about 

 2,7 (T, is damped by the application of the condenser method and 

 that the time constants 7' of O.tU) and 0,(S0 o, obtained i>y means 

 of capacities of 0.6 and 0.7 microfai'ad. are re(|iiired in oi^h-r to 

 reach the desired limit of aperiodicity. 



In tig. 5, where a capacity of 0,6 ƒ/ƒ'. is nsed, the iiniil lias not 

 yet fully been reached, in tig. (> the limiting vahie has already l)een 

 passed Avith a capacity of 0.7 /</'. 



The two last-mentioned plates show that the motion of the string in 

 the neighbourhood of this limit is not very simple. In the small oscil- 

 lation which has remained in tig. 5 the string, after having deflected 

 through 30 mm., passes the new position of equilibrium by 0.5 mm. 

 and then returns to a point which is still 0.3 mm. lower than the 

 position of equilibrium. The ratio of the values of these deliections 

 does not agree with the laws which damped motions generall}' obej'. 

 Moreover the tirst turning-point is reached after 2 (7, the second after 

 1 G, wdiereas with damped vibrations, such as genei'ally occni-, these 

 times are equal. 



In tig. 6 the string comes to rest after about 0.002 sec. at a 

 distance of 0.3 mm. from the new position of ecjuilibrium and reaches 

 its e([uilibrium after a small movement in the opposite direction. If 

 in the measurement of a current one is contenteil A\ith an accuracy 

 of 27o the result is known in about 1,5 a. 



Another example is found in tigs. 7 and 8 of the plate. These 

 pliotograms were taken in the same way as those immediately 



1) The process l)y whieli tlie photograms of tlie plafe have been reproflnced 

 (loe.s not reveal llie niinor details of the eiu'ves. I shall he pleased to send diieet 

 photographic copies of the original negatives to those who are interested ui tliein. 



