180 OWEN'S DESCEIPTION OF TWO NEW MINERALS AND A NEW EARTH. 



The analysis of the mineral is therefore as follows : 



H— Water 18. 



Si — Silica ... - 42. 



Mg — Magnesia 20.5 



New earth 10 to 12 



Al — Alumina .......... 4.6 



Fe — Peroxide of iron 1.5 



K— Potast - , 0.8 



Mn, A mere trace. 



It was found exceedingly difficult to free this earth entirely from oxide of iron and 

 magnesia. I succeeded, however, in separating the iron by the following process, so 

 that the solution no longer gave the reaction indicative of iron either with hydro- 

 sulphuret of ammonia or ferro-prussiate of potash. The solution was evaporated 

 nearly to dryness, and while still hot a jet of water was thrown on it. By repeating 

 this process several times the oxide of iron was all precipitated, and could be separated 

 by filtration, though the solution passed with extreme slowness through the filter 

 from the free state of the precipitated oxide of iron. The magnesia was separated by 

 two methods, either by dissolving the earth in hydrochloric acid, adding sal ammoniac 

 and neutralizing with ammonia, or, by digesting the earth in water acidulated with 

 a few drops of nitric acid. In consequence, however, of the new earth being slightly 

 soluble in sal ammoniac and in dilute nitric acid some loss is sustained by this method, 

 and therefore it is not applicable to quantitative analysis. 



When thus separated this earth has the following properties and reaction with 

 reagents. 



It dissolves readily either in hydrochloric or nitric acid, evolving chlorine from the 

 former acid. The solution in hydrochloric acid, when concentrated, has a beautiful 

 pea green colpr, and the salt crystallizes either of a slightly paler green or a light 

 chrome yellow, depending on the degree of heat at which the evaporation is completed. 

 The peculiar color of its salts together with the appearance of the residue left in the 

 analytical process after treatingwith caustic potash to separate the alumina was what 

 first attracted my attention to this earth. 



The solution of the earth in dilute hydrochloric acid gives the following reactions 

 with reagents : •» 



Ammonia, a white, bulky precipitate, only sparingly soluble in sal ammoniac. This 

 is one of the characters which distinguish it from magnesia. 



Oxalate of ammonia, a white precipitate in neutral solutions : another distinction 

 between it and magnesia. 



Oxalic acid, no precipitate until quite neutralized by ammonia. 



