Action of the Atmosphere vpon neiuly-deepened Soil. A67 



variation coincides very generally with the boundary-lines of the 

 different formations ; so that, if the scale be sufficiently large, the 

 relative fertility may, in some cases, be traced even across fields, 

 portions of them being far more productive than others." 



Although the varieties of geological strata are almost endless, 

 yet they are found to be, for the most part, ultimately derived 

 from a few kinds of simple minerals, such as quartz or silica, 

 felspar, mica, hornblende, limestone, &c. ; and the best way to 

 serve the purposes of this paper seems to be to take up each of 

 these in succession, and show how it is affected by the atmos- 

 pheric influences. To save space, their chemical composition, 

 derived from the examination of the best analysts, is given 

 together in one Table. 



Minerals. 



Authority. 



Water. 



(juartz 



Felspar, orthoclase . 



„ albite . . 



„ Jabradorite . 

 oligoclase 



Compact felspar . . 



Mica, potash . . . 



„ lithia .... 

 „ magnesia . . 



Chlorite 



Talc 



Steatite 



Serpentine .... 

 Hornblende, common 



„ basaltic . . . 



„ „ decomposed 



„ tremolito . . 



„ actinolite . . 



„ asbestus . . 

 Aiiglte, common . . 



„ decomposed . 



sahlitc 



Diallage .... 

 Kpidote, common . 

 Olivine .... 

 Kaolin .... 

 Greencarth . . . 



dauconito . . . 

 2eolite, uiiaU inn' . 



„ natrollte . 



„ gcolczitt! . 



„ npopliyllite 



,, cliabasitc . 



Calcareous spar . . 



Rose . 



Klaproth 



G. Rose 



Klaproth 



Berzelius 



Klaproth 



H. Rose 



KUiprull 



