512 Prof. Riicker. On the Magnetic Permeability of 



Zero 0-00 



Deflection -with tube in 7'31 



after 30 mins.. . 7'00 



Zero O'OO 



Deflection with tube in 8*38 



after 30 mins,. . 8'11 



During the first few minutes no appreciable falling off was observed, 

 so that, as the time required for an experiment does not exceed a 

 minute or two, any error arising from this cause may be neglected. 

 Care was also taken to rotate the tubes frequently, and to empty them 

 and pour the liquid in again at short intervals. In order to test the 

 accuracy of the whole arrangement, several series of experiments 

 were made with the apparatus set up in different positions, and the 

 values obtained were such as to show that no serious discrepancy 

 existed. In the following table the fractions in the first column are 

 the ratios of the volumes of the standard mixture of water and 

 magnetic oxide to that of the glycerine, and they may therefore be 

 called the strengths of the mixtures. In the other columns are the 

 susceptibilities obtained in each case with a completely different 

 arrangement of the apparatus. 



Six weeks after the last of the preceding series had been taken, 

 another set of experiments was made in order to test the invariability 

 of the magnetic properties of the mixtures. No change whatever 

 could be detected, as will be seen from the following table of 

 results : 



