236 QUARTERLY JOURNAL. 



Mica Slate Soil. Granitic Soil. 



Potash, 2.2 trace. 



Peroxide iron and alumina, .... 5.6 6.8 



Soda, 2.5 " 



Lime, 3.2 0.3 



Magnesia, 1.2 0.8 



Loss, 0.1 0.0 



100.0 100.0 



Hornblende and sienite make, also, a much better soil than gra 

 nite, and trap rocks, than either, as it decomposes more rapid!] 

 and furnishes the alkalies, potash, soda, lime and magnesia j whild 

 at the same time, it is warm and light. 



Argillaceous rocks give origin to a tough blue or brownisf 

 colored soil, and is cold and heavy ; but is capable of being im- 

 proved, by underdraining and admixture of sand. Limestone soils 

 differ from the above, as much as the nature of the rock itself dif 

 fers from it ; though the lime is often removed by filtration and so- 

 lution, and by the action of plants, when it contains principall) 

 the silicates and alumina. 



Under the second head, it is maintaiied that those plants whicl 

 abound most in inorganic matter, were first formed, as lichens 

 ferns and the grasses. These plants laid the foundation for organi( 

 matter in the soil, as they would consolidate a sufficiency of car 

 bon to furnish the mould for other plants. Plants of the highe 

 orders, when grown in pulverized quartz, with saline matter only 

 do not produce seed, though the foliage grows well. When th' 

 plant dies, a mould or humus is formed, and the next crop perfec 

 their seeds. Peat has a similar origin with mould ; that is, fron 

 the death of plants, as the mosses, growing in water togethe 

 with the leaves, stems and roots of other vegetables. Peat pre 

 serves wood and even animal matter from decay when wholly sub 

 mersed ; but w^hen atmospheric air has access to those matters 

 they decay. Peat contains nitrogen, phosphate of lime, and some 

 times phosphate of magnesia. Sometimes peat spread upon soil 

 exerts an injurious effect, from the presence of free acids. Som 

 salts, as copperas, and sulphate of alumina, are present in excess 

 these exert an injurious effect. These facts explain to us why i 

 is, that some farmers are justly prejudiced against peat as a ma 



