484 Intelligence and Miscellaneous Articles. 



dimmish the magnetic rotatory power of the solution. M. E. Bec- 

 querel has made an analogous observation upon the protochloride of 

 iron, and he believed that it might be said in a general why, that 

 the rotation of the plane of polarization due to the influence of mag- 

 netism varies in an opposite ratio to the magnetic power of the 

 bodies. The experiments referred to by M. E. Becquerel do not 

 allow us to consider this law as absolute. Thus we see by them, 

 that the rotation of water being represented by 10, those of the two 

 unequally concentrated solutions of protochloride of iron are repre- 

 sented by 9 and by 3, and that of a solution of sulphate of nickel by 

 13*55; in other words, of these magnetic solutions there are two 

 which produce a weaker rotation than water, whilst the third pro- 

 duces a stronger one. Nevertheless, the extreme weakness of the 

 rotation of a concentrated solution of protochloride of iron, approach- 

 ing the observation of M. Bertin on the protosulphate of iron, seems 

 to indicate that there is a peculiar mode of action in the ferruginous 

 compounds deserving of careful study. 



I have dissolved in water a certain number of proto- and per-salts 

 of iron (chlorides, sulphates, nitrates), and found that in all cases the 

 rotatory power of the solution was less than that of water. But 

 what is more, if, taking into account the density and composition 

 of the solution, we calculate the rotation that would be produced by 

 the quantity of water alone which it contains in a given thickness, 

 we find a number constantly superior to the rotation observed. 

 Things take place therefore as though the dissolved iron salt pos- 

 sessed a rotatory power in the opposite direction to that of water. 



I proposed to ascertain whether this hypothesis was the true 

 explanation of the phaenomena, and I think I have succeeded in pro- 

 ving it. After numerous fruitless attempts to procure a solid or 

 readily fusible ferruginous body, sufficiently transparent with a 

 thickness of 1 to 2 centimetres, and not exerting of itself any action 

 upon polarized light, I succeeded completely by dissolving the salts 

 of iron in vehicles, such as alcohol and aether, capable of taking up 

 a considerable quantity of the salt, and endowed with so weak a mag- 

 netic rotatory power, as to show the direction of the rotatory power 

 of the dissolved compound. Thus by mixing 8 grammes of anhy- 

 drous perchloride of iron with 32 grammes of rectified sether, I 

 obtained a liquid of a strong red-brown colour, but perfectly limpid, 

 which under the influence of magnetism deviated the plane of polar- 

 ization to the left under circumstances in which water and other 

 transparent substances deviate it to the right, and vice versd. With 

 32 grammes of sether and only 4 grammes of the perchloride, I 

 obtained a liquid which, under the influence of the electro-magnet 

 which I had at my disposal, scarcely exerted any action upon polar- 

 ized light. Alcoholic solutions gave me exactly similar results. 

 Moreover, it is easy to ascertain that the ajtherial or alcoholic solu- 

 tions of alkaline or metallic salts behave in general like aqueous 

 solutions. It is therefore to the iron salt dissolved in sether or 

 alcohol that we must attribute the remarkable phaenomenon which 

 I have just made known, and from this we must conclude that the 



