SCIENTIFIC WRITINGS. 411 



obscure, were cleared up. I arrived thereat by ex- 

 periments with tubular e]ectro- magnets, which gave 

 the looked-for result that iron exerts no, or at any 

 rate no appreciable, protection against magnetic action 

 at a distance, and that the magnetic maximum of iron 

 is independent of the direction of the magnetism. From 

 this it follows that the magnetism called forth in iron 



D 



by a magnetizing force is diminished by a simultaneous 

 magnetization in another direction. The maximum 

 magnetization occurring in ring -magnets even with 

 feeble magnetizing power shows that the strengthening 

 magnetizing effect, which magnetized iron molecules 

 exert on their neighbours, considerably outweighs direct 

 magnetization. This led me to the modification al- 

 ready previously adopted by Stefan, as I afterwards 

 found - - of Weber's electro-magnetic theory, according 

 to which the assumed elementary solenoids must be 

 double solenoids, which as such move about freely in 

 space, and are directed by a magnetizing force acting 

 upon them, and then rotate round one another in a 

 scissor-like fashion. If we suppose the whole universe 

 to be filled with such double solenoids, which after 

 the theory of Father Secchi and Edltmd might be con- 

 ceived as ether -vortices, and that iron and the other 

 magnetic bodies were distinguished from the non- 

 magnetic by the ether -vortices pre-existing in a unit 

 of volume being more numerous in the former than 

 the latter and in empty space, magnetic action at a 

 distance might also be regarded according to Faraday's 

 suggestion as an action proceeding from molecule to 



