758 PLUCKER ON THE DETERMINATION OF THE 



ported by both being modified in the same manner by heat ; this 

 view has already been shown to be borne out by both exhibiting 

 polarity. 



66. A series of important questions is connected with the 

 above experiment ; which was also subsequently repeated in a 

 porcelain cup, and the same result obtained. 



Is there a limit to diamagnetism, so that at a certain degree of 

 temperature it entirely disappears or is reduced to a minimum, as 

 is the case with the magnetism of iron, or other magnetic metals? 

 In the case of bismuth this limit would lie between 572° and 

 752° F. 



67- During the last experiment the state of aggregation of the 

 bismuth became changed. It occurred to me to investigate by 

 experiments with other diamagnetic substances, whether the 

 transition from one state of aggregation to another exerts any 

 influence upon the intensity of the diamagnetism; such indeed 

 does not appear to be indicated by the last weighings. 



I first selected stearine. This was fused exactly as in the ex- 

 periment with bismuth, in the same brass cup, and heated con- 

 siderably above the boiling-point. On applying a current of the 

 same intensity, it proved to be always equally diamagnetic, even 

 during its solidification, and until it acquired the temperature 

 of the room ; at least the difference in the attraction of the cup 

 filled with stearine did not amount to 5 milligrms. 



68. 7'5 grms. of sublimed sulphur were then taken, fused in 

 the hemispherical porcelain cup, and heated above its point of 

 fusion. The cup was 45 millims. in breadth at the top ; but as 

 it was not sufficiently magnetic to overcome by its attraction the 

 repulsion of the substance within it, a rod of iron 60 millims. 

 in length and 4 millims. in diameter was axially directed, and 

 fixed by means of wax to the corresponding end of the beam, as 

 in a former experiment. On using ten cells and fresh nitric 

 acid, a weight of 



1-200 grm. 



was required to sepai'ate the empty porcelain cup. On insti- 

 tuting the experiment as before, and counterpoising again after 

 each experiment, the following weights were found requisite to 

 separate the cup containing the sulphur, which was at first in a 

 state of fusion, but after the third weighing began to solidify, 

 from the halves of the keeper : — 



