553 



Article XVI. 



Experimental Researches on the Action of the Magnet upon 

 Gases and Liquids'^, By M. Plucker, Professor of Natural 

 Philosophy hi the University of Bonn. 



[From PoggendorfF's Jnnalen, March 1848.] 



1. As subject of the present, which is my third communica- 

 tion, 1 have selected from my experimental researches upon the 

 action of the magnet, two classes of phaenomena — one of which 

 relates to the magnetic or diamagnetic action of the magnet upon 

 liquids, the other to its action upon gases. In the observation 

 of the former I adopted a different method from that of Faraday j 

 I observed the motions of the various liquids above the approxi- 

 mated poles of the magnet, and the alterations produced by the 

 poles in the form of the surfaces. When, as in the blood, minute 

 corpuscles are suspended in the liquid, the microscope may be ad- 

 vantageously called in aid to observe their motions. In all these 

 experiments I found Faraday's results completely confirmed. 

 Not so, however, with regard to the reactions of gaseous bodies ; 

 for ia this case my experiments led me to results which com- 

 pletely contradict the statement of this philosopher, that bodies, 

 in passing into the gaseous state of aggregation, become indif- 

 ferent to magnetism. I communicate these results with that 

 diffidence which becomes me in opposing so great an experi- 

 menter. 



2. In my investigations I made use of the horseshoe electro- 

 magnet, which has been described in the second paragraph of 

 my first memoir (p. 354) ; this stands perpendicularly, so that 

 the surfaces of its poles are directed upwards. To allow of the 

 increase of the magnetic tension in different ways by the ap- 

 proximation of the poles, polished pieces of iron of various forms 

 were applied ; and these being united in pairs, formed the keeper. 

 They consisted of, — -first, two parallelopipedal halves of the 

 keeper (A), which have been mentioned in paragraph 44 (p. 3/2) 

 of the previous memoir, 27 millims. in height, 67 millims. in 

 breadth and 1 98 millims. in length ; secondly, two halves of the 



• Translated by Dr. X. W. Griffith. 

 VOL. V. PART XX, 2 P 



