( 244 ) 



to a f>reat extent eliminated if the measurements at the lower side 

 of the string are coiitroUed by measurements at the upper side. 



The most likely explanation has to be sought, in my opinion, in 

 the lack of homogeneity of the magnetic field. The middle part of 

 the ((uartz thread is placed between the objectives of the microscopes, 

 where the magnetic field is only very feeble compared with the 

 field in which the other parts of the thread are placed. The pondero- 

 motive force which causes the quartz thread to deflect, when it is 

 passed by a current, is consequently smaller in the middle of the 

 string than at the two ends. These latter, so to say, draw aside the 

 middle part and so it can be understood that with feeble tension of 

 the quartz thread the displacement of the middle part higs. 



The stronger the tension of the quartz thread the more regularly 

 it Avill move over its Avliole length. So we may expect that for a 

 less sensitive position of the galvanometer the values which we must 

 take for m will be more equal among each other. 



In tables XI and XII and figure 4 belonging to them, we will 

 first give the analysis of a curve written by string n". 14. The tables 



Fig. 4. 



Stiing W. li, photogi-am A 13^2, Tables XI and XII. 

 Absciss 1 scale division = 2t, ordinate 1 scale division =^1,72X10"^ Amp. 



