PRINCIPLES OF ROCK IVEA THERING 



721 



table shows (i) the percentages of the various constituents 

 thus taken out by the carbonated water and (2) the total 

 percentages of the materials dissolved. That is to say, the 

 figures 0.1552 given for adular under SiOg, indicate that 0.1552 

 per cent, of the total 65.24 per cent, of the silica contained by 

 the mineral has been removed, and so on. The last column, on 

 the other hand, gives the total per cent, of the entire rock of all 

 the constituents extracted. 



The summary of his investigation is given as below: 

 (i) All the minerals tested were acted upon by the carbon- 

 ated water. 



(2) In this process there were formed carbonates of lime, 

 iron, manganese, cobalt, nickel, potash and soda. 



(3) In the action of the carbonated waters upon the alkaline 

 silicates like the feldspars, a small amount of silica went always 

 into solution, presumably in the form of hydrate. 



(4) Even alumina was dissolved in appreciable quantities. 



(5) Adular proved more resisting to the action of the acid 

 than did oligoclase. 



(6) The first stage of decomposition in the feldspars was a 

 reddening process ; the second, kaolinization. 



(7) Hornblende was more easily decomposed than feldspar. 



(8) Increase of pressure on the solution was productive of 

 more energetic action than prolonging the time. 



(9) Of all the minerals tested, the magnetic iron was least 

 affected. 



