NATURAL PHILOSOPHY. 133 



the rhomboidal prism, so that, when a long crystal is used, it will not, 

 as a mass, point between the poles, but across the line joining them. 

 On the other hand, sulphate of nickel has its magnecrystallic axis 

 parallel, or nearly so, to the length of the ordinary prism. Diamond, 

 rock-salt, fluor-spar, boracite, red oxide of copper, oxide of tin, cin- 

 nabar, galena, and many other bodies, presented no evidence of the 

 magnecrystallic condition. 



Having thus stated the effects produced, Dr. F. enters upon the 

 consideration of the nature of the magnecrystallic force. He found 

 that bismuth has the same amount of repulsion when presenting its 

 magnecrystallic axis parallel or transverse to the lines of magnetic 

 force acting on it, and he was led by an ingenious series of experi- 

 ments to conclude that it is neither attraction nor repulsion which 

 determines the final position of a magnecrystallic body. 



He next considers it as a force dependent upon the crystalline con- 

 dition of the body, and, therefore, associated with the original mo- 

 lecular forces of the matter, and shows experimentally, that, as the 

 magnet can move a crystal, so also the crystal can move a magnet ; 

 and, also, that heat takes away this power just before the crystal 

 fuses, and that cooling restores it in its original direction. Coming 

 next to the question, whether the effects are due to a force altogether 

 inherent in the crystal, or whether they are not partly induced by 

 the magnetic or electric forces, he concludes that the force manifested 

 in the magnetic field, which appears by external actions, and causes 

 the motion of the mass, is almost entirely induced, in a manner subject, 

 indeed, to the crystalline force and additive to it, but at the same time 

 exalting the force and the effects to a degree which they could not 

 have approached without the induction. To this part of the force he 

 applies the word magneto-crystallic, in contradistinction from the word 

 magnecrystallic, which is used to express the condition, quality, or 

 power which belongs essentially to the crystal. The author then con- 

 tinues his investigations, and concludes with some appropriate remarks 

 on the progress recently made in the knowledge of magnetism, its 

 powers and effects. 



MAGNETIC ACTION ON RAILWAYS. 



IT is well known that an opinion has prevailed among scientific men 

 for a few years, that railway axles, after having been used for some 

 time, become crystallized by galvanic action, and are then very easy 

 of fracture. The subject was brought before the late meeting of the 

 British Association by Mr. Greener, who, without questioning the 

 fact, stated that the axles were affected with electricity generated by 

 the bearings and the journal while in rapid motion. He said, that by 

 subjecting inferior iron to currents of electricity, it was soon changed 

 into a crystalline state, and lost its tenacity. 



Mr. Stephenson said, that it was dangerous to assume facts and rea- 

 soning from the assumptions of Mr. Greener. With respect to the in- 

 fluence of vibration on the structure of iron, he considered that there 

 was good room to doubt that the bearing force or pressure upon metals 

 caused crystallization. It was by no means proved that railway axles 



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