CHEMICAL ACTION OP WATEB 



169 



one millionth of the powdered, were treated in the same way, 

 and the water renewed every two days, the time required for 

 perfect solution would be somewhat more than six million 

 years." In considering these figures and their practical bear- 

 ing, it must be remembered that while in nature the quantity 

 of water coming in contact with a crystal embedded in a rock 

 during a given time is much less than that assumed above, the 

 mineral is undergoing a gradual splitting up, becoming more 

 and more porous, so that the process is gradually accelerated. 



To quote Bischof again, it is probably admissible to assume 

 that the time in which water produces similar effects of decom- 

 position or solution on minerals, is inversely as the magnitude of 

 the surface of contact. If, therefore, a mineral were so far subdi- 

 vided that the surface was increased ten million-fold, the quantity 

 then dissolved during a given time would be the same as that of 

 the undivided mineral during a period ten million times as long. 



Eichard Miiller has also shown^ that carbonic acid waters 

 will act even during so brief a period as seven weeks upon the 

 silicate mineral with such energy as to permit a quantitative 

 determination of the dissolved materials. The accompanying 

 table from his paper shows (1st) the percentages of the various 

 constituents thus taken out by the carbonated water, and (2d) 

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

 the figures 0.1552 given for adular under SiOs, indicate that 

 0.1552% of the total 65.24% of the silica contained by the min- 

 eral have been removed, and so on. The last column gives the 

 total per cent of all the constituents extracted. 



SOLITBILITT OF MINERALS IN CaEBONIC AcID 



MiNBBAL 



SiOa 



Al,0s 



KjO 



N-a^O 



MgO 



CaO 



PaOs 



FeO 



Total 





/o 



% 





% 



% 



0/ 



/o 



% 



% 



% 



Adular . . . 



01662 



0.1368 



• » » « 



• * * * 



« « • ■ 



.... 



• « * » 



trace 



328 



Oligoclase . 



0.237 



9.1713 





2.367 



• • • • 



3.213 



« * • « 



trace 



0.533 



Hornblende . 



0.419 



trace 



■ • • • 



. . > ■ 



* * * • 



8 528 



a « « • 



4 829 



1.636 



Magnetite . . 



trace 



• • • * 



• ■ ■ • 



... * 



* • fe • 



.... 



* » ■ * 



942 



0.307 



Apatite . , . 



.... 



• • * • 





* • • ■ 



• • • • 



2168 



1.822 



.... 



2.018 



Olivine . , . 



873 



trace 



• • • • 



. ♦ • • 



1.291 



trace 



t . • • 



8.733 



2111 



Serpentine . 



0.364 



. • • 



.... 



.... 



2.649 



• • « • 



.... 



1.627 



1.211 



^ XJntersuchen iiber die Einwirkung des kohlensaurebaltigen "Wassers auf 

 einige Mineralien nnd Gesteine, Tscbermabs Min. Mittbeilungen, 1877, p. 25. 



