PLUCKER ON THE THEORY OF DIAMAGNETISM. 359 



between magnetism and magnecrystallic deportment, there is 

 a strict analogy between his classification and the above. I 

 have no desire to impugn the accuracy of the statement, that 

 the independence contended against was never meant to be 

 asserted ; I only urge that the fair grammatical interpretation of 

 the language used would lead any body to suppose that it was 

 meant, and this, I trust, will justify me in the course which I 

 have taken, even recently, in connexion with this subject. Few 

 have given more attention to the question before us than M. de 

 la Rive, and few I think understand it better. Let us inquire 

 how he has interpreted the words of Prof. Pliicker. In the 

 English translation of his valuable treatise on electricity, he 

 states the view of this philosopher to be, " that the axis, in its 

 quality of axis, and independently of the very nature of the 

 substance of the crystal, enjoys peculiar properties more fre- 

 quently in apposition (opposition ?) to those possessed by the sub- 

 stance itself, or which at least are altogether independent of it.^^ 

 There is undoubtedly an approach to the true solution of the 

 question in the foregoing memoir. We obtain from the perusal of 

 it the conviction, that had M. Pliicker been left to the undis- 

 turbed prosecution of the subject, he would finally have com- 

 pleted his valuable discovery by the development of its true 

 laws. Still, although the tendency is in the right direction, the 

 end is far from being attained. The fundamental cause of all 

 magnecrystaUic phaenomena is, that the mass is attracted or 

 repelled with peculiar force in one or more directions, a fact first 

 established in the case of bismuth by Faraday. In the memoir 

 before us this cause was not only not assigned, but a series of 

 experiments were cited for the express purpose of disproving its 

 existence. On this cardinal point M. Pliicker has the candour 

 to admit himself in error. It might be readily inferred from 

 this and other papers that M. Pliicker had been misinterpreted; 

 sufficient, I trust, has been said to show, that, if such has been 

 the case, the mistake was not wilful, and also to prove, that 

 however quickly the foregoing memoir might have been printed, 

 it would by no means have rendered the researches which have 

 been since made unnecessary. — J. T. 



