756 PLUCKER ON THE DETERMINATION OF THE 



63. To determine the influence which heat exerts upon the 

 diamagnetism of bodies, I first took bismuth. In the brass cup 

 mentioned in paragraph 60, I fused 116 grms. of this metal; it 

 was heated to beyond the point of fusion, and then placed above 

 the pole of the magnet. The magnetism was excited by eight 

 Grove's cells (the nitric acid had been used once previously). 

 After the attraction of the empty cup had been found to be 



1-97 gvm., 

 the attraction of the cvip containing the fused bismuth was de- 

 termined in the manner described above ; and during the gradual 

 cooling and solidification of the bismuth, these determinations 

 were continued, without opening the circuit, until the mass had 

 again acquired the temperature of the room. 



In the first experiment, the weights requisite to produce the 

 separations successively were — 



0-95, 0-76, 0-41, 0-37, 035, 0-235, 0-19, 0-35, 0-38, 

 0-35, 0-35 grm. 



The first experiment proved beyond a doubt, in opposition to 

 the expectation which I had based upon Faraday's opinion, that 

 the intensity of the diamagnetism diminishes at more elevated 

 temperatures. The relative measure of these for the limits of 

 temperature in tlie experiment was 



1-02 and 1*62 grm. 



A glance at the results of the weighings gives rise to the sup- 

 position that during the sixth and seventh weighing the balance 

 was not in perfect order. This being premised, the diamag- 

 netism ceases to alter Avhen the bismuth has cooled down to a 

 certain temperature. The third before the last only would then 

 contain a small error, which is easily explained by the nature of 

 the process being one in which haste is unavoidable. 



64. The same experiment was repeated, with every precaution, 

 in the same manner, except that ten Grove's cells (with nitric 

 acid which had been once previously used) were applied, and 

 the fused bismuth was of a higher temperature. The attraction 

 of the empty brass cup amounted to 

 2*15 grm. 

 The weighings, which were then uninterruptedly continued in 

 succession, and in which counterpoise was effected by means of 

 paper and fine sand, yielded the following results: — 



