200 agricultural repout. [1~355 2 , 356, 357, 358 



find associated with the coal beds ; we often discover in them, in a compressed 

 condition, the roots, with parts of the trunks, leaves, etc., of the plants which 

 have furnished the materials for the overlying coal. In the same manner we 

 often find in the Lignitic formations of our own State, dark colored, sandy clays, 

 filled with the vestiges of an ancient vegetation, the roots and parts of the trunks 

 of which are still in their original position. Two beautiful instances of this kind, 

 occurring in this State, have been mentioned in the Geological Eeport (244 ; 

 249). But in both these cases, the materials surrounding the fossil roots would 

 be totally unsuited, in their present condition, to the growth of analogous plants, 

 at present existing. Even though they may still contain the same elements of 

 fertility which enabled them to produce the forests we now find buried, their 

 physical condition has been greatly altered ; they have become dense, compact 

 and semi-indurate. Nor are the chemical changes they have undergone of less 

 moment. 



355 2 The action of the atmosphere would gradually restore these ancient 

 soils to their original condition. It is to the same agency, slowly but surely dis- 

 integrating even the hardest rocks, that we owe the lormation of our soils, at the 

 present time ; if, therefore, we would understand the nature of soils, we must 

 make ourselves acquainted with the mode ot action of the causes just alluded 

 to, among which the following claim our chief attention, viz : 1. The mechanical 

 action of water, by attrition and transportation of materials, or what is techni- 

 cally termed denudation. 2. The effects produced by changes of temperature, 

 such as frost, and changes from wet to dry and vice versa; with the effects of 

 both of which, in pulverizing soils, agriculturists are familial'. 3. The chemical 

 action of the constituents of the atmosphere (excepting nitrogen, which is inert), 

 viz : water, carbonic acid, oxygen, and ammonia. 



356. M< st locks aie c\ mposed ot several minerals, seme of which are more 

 readily decomposed by the action of the aimtsjhere than others; m*oieo\er, 

 small J arti< les ol one and the same mineral disint* grate sooi er than li ig <'i es. 

 Usually, therefore, locks aie softened, and theii particles made susceptible of 

 being carried oft by the rains, long keixfre the chemical decempcts't ion oi the 

 several minerals bat been completed. It follow* as a eonsequtnee, that in soils 

 thus loaned v\ e have to dist nguish tv\o diflerent \ oitions, viz: that which c< n- 

 sists of minerals undecemposed, or in process ol dec< m position ; and that which 

 isloimcd by the deccvipoaition cf the several onirierals. 



357. Falltwing — '\ he process of decent} csiiicn does not, of course, cease 

 after the particles of the icck have 1 ten carried away 'urn then oi ig nal places. 

 On the contrary, its progiess geneialh been mes more rap d, in cor.stqutnce of 

 the cemminution caused ly the ti asportation; it is constantly active in our 

 soils, and its efitcts aie m« st str kn gly perceived vel en 1; no is fqlidfied, i. e. 

 exposed to tl e action of the atmesj here for me or seveial seasons, v\ ltboi t ci op- 

 ping. In the fiesh, undetomj cscd portion of the soil, the mineial ingredients 

 which p. ants require aie contained in a condiben in which ibey are not immedi- 

 ately available for absolution into the vegetable ec one my — lodedip as it were. 

 In the natural couise ot things the action of the utmcspheie very gradually 

 uncloses these hidden treasuies ; but we can very mucb accelerate the pi ogress 

 of decomposition by the ut-e ot the so-called stimulant manures, ot which 1 shall 

 speak beieafter ; and the beneficial eflects of thorough tillage are also due, to no 

 small extent, to the increased accessibility oi the soil, to the decomposing action 

 of the atmosphere. 



PRINCIPLES OP AGRICULTURAL CHEMISTRY. 



358. Important, and almost indispensable as it is, that any one who would 

 avail himsell, to its full extent, of the aid which scieice can give to tie piaetical 

 agriculturist, should be acqnanted with the iucI ments at kast ot el em stiy, it 

 would divert me too lar horn the put pose ol the piestnt Revolt, should 1 give, 



