1 1 PHYSIOGRAPHY. 



melts in all proportions. If much of the mineral is added, 

 the globule turns opake on cooling, but does not deposit 

 any fumes of zinc on the charcoal. The globule obtained 

 from fusing it with borax does not become opake on cool- 

 ing. With soda it gives a scoria, which is yellow when 

 hot ; copious fumes of zinc> and nearest the scoria also some 

 of cadmium are deposited. The melted mineral forms a 

 fine blue glass with solution of cobalt. Hopeite seems 

 therefore to be a compound of some of the stronger acids, 

 as phosphoric or boracic acid, of zinc, an earthy base, a little 

 cadmium, and a great deal of water. 



It has been hitherto found only in the calamine mines of 

 Altenberg near Aix-la-Chapelle, and is very rare. 



HUMBOLDTINE. 



Humboldtine. MARIANO DE RIVERO. Ann. de Chimie. 



Crystals belonging to the pyramidal system, accord* 

 ing to HAUY ; massive plates. 



Colour bright yellow. 



Soft, yielding to the nail. Sp. Gr. == 1-3. 



Acquires resinous electricity by friction. 

 According to RIVERO, it consists of 



Protoxide of Iron 53-56. 

 Oxalic Acid 46-14. 



On ignited charcoal it is decomposed, giving out a vege- 

 table odour, while the colour of the remaining oxide of 

 iron is changed into different shades of yellow, then black, 

 and at last red. It is insoluble in water and alcohol. It 

 occurs imbedded in moor-coal, near Bilin in Bohemia, and 

 is supposed by RIVERO to have been produced from the 

 decomposition of succulent plants. 



HUMITE. 



Humite. BOURNOH. Cat. p. 52. PHILL. p. 205. 

 Form prismatic, according to PHILLIPS ; combina- 



