22 GEOLOGY OF SOIL. 



A distinguished authority in our country, Prof. Norton, of 

 Yale, formerly the pupil and assistant of Prof. Johnston, 

 speaking of very fertile soils, says that these always con- 

 tain "appreciable quantities of some ten or twelve sub- 

 stances. It makes no difference from whence you bring 

 such a soil, from what part of the world it comes, it will 

 invariably contain these elements in greater or less quantity." 

 (Agr. Address, Northampton, 1849.) Fertile soils are not 

 confined to particular rock formations; they are found 

 overlying all formations, — they are so independent of the 

 rock beneath, that they invariably contain similar elements. 

 Though it may seem premature to place before all who . may 

 read this work the results of analysis, before they have 

 become familiar with chemical names ; yet those here used 

 are so common, that the proof adduced may not be misun- 

 derstood. 



The analysis of the ashes of plants grown on different 

 geological formations, in soil which is stated to have pro- 

 ceeded from the decomposition of the underlying rock, 

 proves how little dependent is the plant on the chemical con- 

 stitution of the soil. The ashes of the grape-vine, grown on 

 four different soils, afforded, 



I. II. III. rv. 



Potash, 34.13 24.93 26.41 37.482 



Soda, 7.59 7.00 8.57 1.336 



Common salt, . . . 0.83 0.58 0.41 1.614 



Lime, 30.28 35.94 31.78 34.344 



Magnesia, 4.66 7.12 9.16 1.055 



Phosphate of lime, 15.694 



Sulphate of lime, . . 4.55 4.02 4.13 6.186 



Peroxide of iron, . . 0.16 0.24 0.19 1 .564 j- ^^^Pjlf^J^ 



Phosphoric acid, . . 16.35 19.55 16.87 



Silica, 1.45 0.62 2.48 0.725 



