ISOMORPHOUS RELATIONS OF MANGANESE. 539 



the solution into a tubulated retort, and adding by degrees 

 small portions of fused chloride of sodium or potassium, that 

 is, salt completely free from water. The hyperchloride of 

 manganese is the result of a reaction between the liberated 

 hyper manganic and hydrochloric acids : 



Mn 2 O 7 and 7H Cl == Mn 2 C1 7 and 7HO. 



A corresponding hyperfluoride of manganese was formed by 

 Wohler by distilling, in a platinum retort, a mixture of man- 

 ganate of potash and fluor spar in powder, with fuming sulphuric 

 acid. It is a greenish yellow gas, which likewise produces 

 purple fumes in damp air. 



ISOMORPHOUS RELATIONS OF MANGANESE. 



The compounds of no element enter into so many isomor- 

 phous groups, and connect so large a proportion of the elements 

 by the tie cf isomorphism as those of manganese. The salts of 

 its protoxide are strictly isomorphous with the salts of magnesia 

 and its class ; so that manganese belongs to and represents the 

 magnesian family of elements. The same metal connects the 

 sulphur family with the magnesian, by the isomorphism of the 

 sulphates and manganates ; and, therefore, sulphur, selenium, 

 and tellurium are thus allied to the magnesian metals. To these 

 there may be occasion to add oxygen, if the reported discovery, 

 by M. Persoz, of a class of hyposulphites isomorphous with the 

 sulphates should prove to be correct. These hyposulphites are 

 compounds of hyposulphurous acid with basic sulphurets, and 

 present a remarkable analogy, in solubility and other properties, 

 to the sulphates, as well as similarity of form. Being sulphur 

 salts, they are termed sulpho-sulphates by Persoz. The sulpho- 

 sulphate of potash is formed by fusing 80 parts of sulphur 

 with 100 parts of dry carbonate of potash, and washing out 

 the sulphuret of potassium with alcohol. 



An equally interesting relation is that of hypermanganic 

 with hyperchloric acid, and the isomorphism, which it esta- 

 blishes, of 2 equivalents of manganese with 1 equivalent of 

 chlorine, and the other members of its family. We are thus 



