752 PLUCKEB OM THE DETERMINATION OF TliE 



58. We have already (23.) found the magnetism of protosul- 

 phate of iron dissolved in water to be equal to 



123, 

 the magnetism of the iron for the same weight being placed at 

 100,000. If in the same space which was previously filled with 

 the unit of weight of the green vitriol, we now diffuse merely 

 the fiftieth part, the magnetism becomes reduced to 



2-5. 

 Its intensity would thus amount to only the 40,000th part of 

 that which occurs with a unit of weight of iron. 



If we assume the same number as the measure of the diamag- 

 netic repulsion of the water, a gramme of water uniformly diffiised 

 within the watch-glass, on using six Grove's cells, would expe- 

 rience a repulsion of about ^o'Wo ~ HUo g^'™- (IS.). Hence the 

 water filling the watch-glass, which Aveighs about 11*5 grms., 

 would suffer a repulse of 



0*14 grm. 

 This number is somewhat greater than that found by observa- 

 tion ; it was obtained with the use of teri cells. 



From this it appears, that if we regard the removal of the 

 magnetism of the green vitriol as a compensating power, a large 

 amount of magnetism is requisite to neutralize a small amount of 

 diamagnetism. 



This result, if it is all generally applicable, is evidently con- 

 nected with the fact, that magnetism increases less in proportion 

 to the increase of the force than diamagnetism, which appears to 

 lead to the conclusion that a greater coercive foi'ce is opposed to 

 the excitation of the latter*. 



If, in the preceding development — but evidently however with 

 less reason — instead of the magnetism of the green vitriol in 

 an aqueous solution, we took the magnetism of the solid green 

 vitriol, we should have 



0-08 grm. 

 as the diamagnetic repulsion of the water in the watch-glass, 

 which would be too little ; for this was found to be the repulsion 

 when ybwr cells only were used. 



§ 5. On the Influence of Heat upon the Intensity of Magnetism 

 and Diamagnetism. 



59. The influence which heat exerts upon magnetism has been 

 a subject of numerous investigations. However, the influence 



* Compare my Memoir of the 21st February 1S48. 



