426 Scientific Intelligence. 



tion in these lines. After noticing the magne-crystallic condition of 

 various bodies, the author enters upon a consideration of the nature of 

 the magne-crystallic force. In the first place he examines closely 

 whether a crystal of bismuth has exactly the same amount of repulsion, 

 diamagnetic or otherwise, when presenting its magne-crystallic axis 

 parallel or transverse to the lines of magnetic force acting on it. For 

 this purpose the crystal was suspended either from a torsion balance, 

 or as a pendulum thirty feet in length, but whatever the position of the 

 magne-crystallic axis, the amount of repulsion was the same* In other 

 experiments, a vertical axis was constructed of cocoon silk, and the 

 body to be examined was attached at right angles to it as radius ; a 

 prismatic crystal of sulphate of iron, for instance, whose length was 

 four times its breadth, was fixed on the axis with its length as radius 



and its magne-crystallic axis horizontal, and therefore as tangent; then, 

 when this crystal was at rest under the torsion force of the axis, an 

 electro-magnetic pole with a conical termination was so placed that the 

 axial line of magnetic force should be, when exerted, oblique to both 

 the length and the magne-crystallic axis of the crystal; and the con- 

 sequence was, that, when the electric current circulated round the mag- 

 net, the crystal actually receded from the magnet under the influence 

 of the force, which tended to place the magne-crystallic axis and the 

 magnetic axis parallel. Employing a crystal or plate of bismuth, that 

 body could be made to approach the magnetic pole under the influence 

 of the magne-crystallic force ; and this force is so strong as to coun- 

 teract either the tendency of the magnetic body to approach or of the 

 diamagnetic body to retreat, when it is exerted in the contrary direc- 

 tion. Hence the author concludes that it is neither attraction nor re- 

 pulsion which causes the seHor determines the final position of a magne- 

 crystallic body. lie next considers it as a force dependent upon the 

 crystalline condition of the body, and therefore associated with the 

 original molecular forces of the matter. He shows experimentally, 

 that, as the magnet can move a crystal, so also a crystal can move a 

 magnet. Also that heat takes away this power just before the crystal 

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

 considers whether the effects are due to a force altogether original and 

 inherent in the crystal, or whether that which appears in it is not partly 

 induced by the magnetic and electric forces ; and he concludes, that 

 the force manifested in the magnetic field, which appears by external 

 actions and causes the motion of the mass, is chiefly, and 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 to magne-crystallic, which is employed 

 to express the condition or quality or power which belongs essentially 

 to the crystal. The author then remarks upon the extraordinary char- 

 acter of the power, which he cannot refer to polarity, and gives ex- 

 pression to certain considerations and views which will be best learned 

 from the paper itself. After this, he resumes the consideration of 

 Plucker's results "upon the repulsion of the optic axes of crystals" 

 already referred to, and arrives at the conclusion that his results and 



