148 ISOMORPHISM. 



to copper, cerium, columbium, lithium, rhodium and ura- 

 nium. 



According to the original law of Mitscherlich, that isomor- 

 phism depends upon equality in the number of atoms, and 

 similarity in their arrangement, without reference to their na- 

 ture, the elements themselves should all be isomorphous. Most 

 of the metals crystallize in the simple forms of the cube or 

 regular octohedron, which are not sufficient to establish this 

 relation. But the isomorphism of a large proportion, if not 

 the whole, of the elements may be inferred from the isomor- 

 phism of their analogous compounds. Thus from the facts 

 just adduced, it appears that the members of the following 

 large class of elements are linked together from the isomor- 

 phism of one or more of their compounds. This large class 

 may be subdivided into smaller classes, between the members 

 of which, isomorphism is of more frequent occurrence, and 

 which are then to be viewed as isomorphous groups. 



ISOMORPHOUS ELEMENTS. 



1. Sulphur 3. Barium 



Selenium Strontium 



Tellurium Lead 



2. Magnesium 



Calcium Titanium 



Manganese 



5. Tungsten 



Molybdenum. 

 Nickel 



Zinc 



Cadmium With two atoms of the P recedin S 



elements. 

 Copper 



Chromium 6 ' ^ odmm 



Aluminum 



Glucinum 



Vanadium Potassium 



Zirconium Ammonium 



7. Chlorine 

 Iodine 

 Bromine 

 Fluorine 



The only known group of isomorphous elements which cannot 



