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t(» he increased 2.9(i times in order to reaeli llie liiiiil ofaperiodioitx . 



Observations with other (|uaft/-threads, the tension of whicli was 

 varied, always uave corresijonchno,- resnUs: willi slronu' tension a 

 small value, with a more feehlv stretched string' a larger \alne of 

 vu- is re(|nired in oi'der to check oscillations. 



It' //'' is kept nnchanged, one has an easy means of accnratcly 

 regnlating the desired degree of damping in a commercial condenser, 

 in which capacities are shnnted in by means of pings in the same 

 way as the resistances of a resistance-box. And it is remarkable that 

 less of the means of damping is snfücient as the oscillations pass the 

 zero-point farther and last longer and conserpiently the Jieed of 

 damping is greater. The phenomenon that, leaving the other circum- 

 stances nnchanged, diminution of the tension only, i.e. — with the same 

 deflection — , diminution of the moving force, changes an aperiodic 

 motion into an oscillatory one, stands quite isolated and has, as far 

 as is known to me, no mechanical or electrical analogon, no more 

 in scientific instruments than in industry. 



We shall Jiow give some results of measurements which although 

 they cannot compensate the lack of a simple formula, may yet be 

 helpful to form an idea of the method in practical work. 



1. When the damping influences already' existing are increased, 

 for example when the electromagnetic damping is strengthened by 

 diminishing the resistance in the galvanometer circuit, a smaller 

 value of T will suffice in order to reach the lindt of aperiodicity 

 when the quartz-thread is the same and the tension is not changed. 



2. If the change in the electromagnetic damping which is caused 

 by varying the value of Wp is taken into account, it makes no 

 dillcrence how^ the single factors ir' and c are chosen. If only their 

 product iv'c = T retains the same value, also the damping influence 

 will remain the same. This latter is only determined by the product T. 



3. If the motion of the quartz-thread is oscillatory it will be 

 observed when the condenser method is applied, beginnijig with small 

 values of T and gradually rising until the limit of aperiodicity is 

 reached, that increasing T does not always cause a reguUir increase 

 of the damping. Especially \vitli feeble tension of the (piarlz-thread, 

 when (mly a few small oscillations are ]iormally [)ro(luced, one sees 

 an irregularity ap[)ear. The addition of a very small capacity can 

 then even slightly enlarge the existing vibrations. 



When such a value of T has once been taken that the limit of 

 aperiodicity is reached, T has oidy little to be raised in order to 

 obtain a regularly shaped curve. With further raising of 7' the motion 



