32 NOMOS. 



pared with those of the unattached atom, which 

 forms the other element, are those of an alkali as com- 

 pared with an acid. He believes, also, that these 

 two opposite elements do actually combine, as an acid 

 with an alkali, to form a salt. According to this 

 theory, then, it is possible to suppose that a metal 

 may be the subject of continual decompositions 

 within itself during the passage of a current, and yet 

 to all outward appearances be never otherwise than 

 the same simple metal. Nor is this theory without 

 foundation ; on the contrary, it is firmly grounded 

 on a fact which cannot well be misconstrued, and 

 which will acquire additional significance hereafter. 

 This is the composition of that strange compound, 

 the magnetic oxide of iron. This is a mixed oxide, 

 consisting of one equivalent of protoxide and one 

 equivalent of peroxide; the first consisting of one 

 equivalent of iron and one equivalent of oxygen, the 

 second of two equivalents of iron and three equiva- 

 lents of oxygen. Neither the protoxide nor the 

 peroxide is magnetic, but this mixed oxide is mag- 

 netic. There is also a magnetic sulphuret of iron, 

 whose composition is analogous to this mixed oxide ; 

 and similar mixed oxides belong to the magnetic 

 metals, manganese and cobalt. Salts of this cha- 

 racter are peculiar to the magnetic metals ; and such 

 being the case, it was quite natural for Prof. Graham 

 to consider this peculiar molecular condition as essen- 

 tially connected with magnetism, and that the con- 

 dition was essentially chemical in its character; 

 though it is not possible to understand the full 

 logical connexions of these ideas without at the 



