THE COLLECTION OF MINERALS 



met, [docrase, Quartz, Mica, Gypsum, Corundum and Spinel, 

 have been so long in use that, like the names of the metals and 

 elements, they must be retained. 



According to chemical composition, therefore, the following 

 principal subdivisions of minerals have been established: 



I. The Native Elements. 



II. The Arsenides, Sulphides, Antimonides, Sulph-arsenides, 

 Sulph-antimonides and similar compounds. 



III. The Haloids. 



IV. The Oxides, anhydrous and hydrous. 



V. The Oxygen-salts, such as Carbonates, Silicates, Phos- 

 phates, Columbates, Tantalates, Sulphates and Nitrates. 



VI. The Hydrocarbons. 



This system is almost universally used to-day. with changes, 



however, more or less material in the succession and interpreta- 

 tion of its various parts, and is practically the production of the 

 century. 

 ( >wing to the early activity of chemical agencies and the still 

 continuing energy of oxygen, a gas which is constantly attacking 

 uncombined elements, the list of Native Elements, as at present 

 known, is much shorter than the list of elements known to chem- 

 istry, a large number of them being precluded from any inde- 

 pendent whatever through their strong affinities for 

 other substances. The mineralogist finds, however, in the 



the earth accessible to him, a small list of native 

 merits, of which six. at the most, are characteristically uncom- 

 bined. while the remainder, about fifteen in number, are found 

 native only und ptional conditions, and one of them, iron, 



irticularly interesting because its most frequent cecum 

 is in the form of meteorites. 



IDE to Tin-: Collection. 



The collect! ted in two halls on the 



i. marked " A " and " B" on tl 



•:i, and is «li | tin- wall case and t lie desk 



exhibil wall ca imens which 



7 



