MINERALOGY. 107 



burns corrosive and becomes almost a metallic calx. The 

 Orders of earth are consequently : 



1. Earth-earths . . . Silica; Quartz, &c. 



2. Haloid-earths . . . Clays; Felspar, &c. 



3. Inflammable-earths . Talcs ; Mica, &c. 



4. Metallic-earths or Ores Calx. 



519. Nature does not produce any so-called pure 

 calcareous earth, but only this earth in an oxydated con- 

 dition. Carbonic acid is the oxygen of the earth that 

 has become free, and the corroding calx is the Metallic, 

 the other constituent part of the Earthy, which has 

 obtained some oxygen, but lost the Aqueous by the car- 

 bonic acid and thereby has become corrosive. 



520. The carbonate calcareous earth is the whole 

 earth, not the corrosive. This is only the half of the 

 earth-element, only its basic or phlogistic principle. 

 What has been called pure calcareous earth is a half 

 earth ; the perfect or nature-historical earth is just that 

 which is chemically impure. 



521. The calcareous earth is not, however, perfected 

 with one position. It still exhibits several stages of de- 

 velopment which appear to be approximations to the 

 salt, e. g. Strontian and Baryta. 



522. The silicious earth, which principally represents 

 the Earthy, holds its principles more firmly together. No 

 separation occurs there in the carbonic acid and the 

 basic or corroding body of earth ; no association with 

 water, no great activity, no direct participation in the 

 highest evolutions of the planet ; but it continues to lie 

 in an extreme state of contraction, and in a state of in- 

 difference in the non- differencing darkness. 



523. This pure earth is the basis, the pedestal of all 

 the other earths, and the foundation of the planet ; for 

 it alone is the earth proper, the earth-abiding earth-ele- 

 ment, while the other masses of earth, divided in their 

 principles, have pitched themselves in outward oppo- 

 sition to the sun and other elements. The silicious 

 earth is in every respect the centre of all earthy pro- 

 ductions, these being only digressions from it. The 



