2 Mr. R. Hunt on the Influence of Magnetism 



low this crystalline plate, but all of them arranged themselves 

 at angles inclining towards the magnet; no crystallization 

 taking place in the upper stratum of the fluid. In the other 

 tube, crystals formed irregularly throughout the fluid, but in 

 no part were the crystals so dense as in the tube which I sup- 

 pose to be under the influence of magnetism. 



2. With a view of determining if the cooling influence of 

 the metal had anything to do with the crystalline arrangement, 

 portions "of the same solution of nitrate of silver were put into 

 glass capsules. One of these was placed against the poles of 

 the magnet, and the other in contact with a mass of brass of 

 the same weight. In the first, crystallization commenced op- 

 posite the north pole of the magnet, and proceeded slowly in 

 regular lines to crystallize over every part ; all these lines have 

 a tendency towards the poles of the magnet. In the capsule 

 in contact with the brass, crystallization commenced at a point 

 furthest from the metal, and even when the fluid had become 

 quite cold, nearly one quarter of it, which was nearest the 

 mass of metal, remained quite free from any crystalline forma- 

 tion. 



3. To exhibit this in a more striking manner, a capsule was 

 placed between the mass of brass and the magnet, in con- 

 tact with each, as shown in fig. 2 ; the solution of nitrate of 

 silver in this case, not being so concentrated as that previ- 

 ously used, the arrangement was allowed to remain at rest for 

 some hours. It was then found that crystallization had taken 

 place only over one portion of the fluid, and that immediately 

 in connexion with the north pole of the magnet, except three 

 long crystals which sprung from the fluid opposite the south 

 pole, and were directed towards those springing from the 

 north pole. This experiment was repeated four times, and, 

 except when the solution was so concentrated as to crystallize 

 almost immediately, the same result was obtained. 



4. The phenomenon of molecular disposition under mag- 

 netic influence is pleasingly seen by a modification of the ar- 

 rangement described. The two glass capsules with their so- 

 lutions are placed on a plate of glass blackened on its under 

 surface, one glass being put in contact with the brass and 

 the other with the magnet. Their images are to be observed 

 in the black mirror on which they rest, the light falling upon 

 them at an angle of about 25°. As the fluids cool, the cir- 

 culating currents coloured by their refracting powers are seen 

 in the mirror. In the image of the capsule in contact with 

 the brass, no regularity of circulatory movement is observable; 

 but in that under magnetic influence, a series of perfectly re- 

 gular curved lines proceed from the circumference to the 



