232 GEOLOGY OF THE THIRD DISTRICT. 



rock exists, and the soil is its product : Why different native growths, not far distant from 

 each other, differ where no cause is apparent, unless from difference in the soil, and tliis not 

 apparent to the senses ? Why land which formerly yielded wheat abundantly, ceases to pro- 

 duce healthy wheat, and that but in small quantity ? A question which could be answered by 

 the analysis of such soil, and the same in a hedge row or elsewhere near by, where the wheat 

 could not be sown. Were the subject pursued in some such manner, the utility of the analysis 

 of soils would doubtless soon be apparent ; but continued in the old or present mode, the good 

 received would be of httle moment. 



The greatest benefit, I should suppose, which is to await the agriculturist, is from rotation ; 

 all other methods being secondary to it. It is the great law which geology makes known, and 

 thereby confirms the first chapter of Genesis, which asserts a succession. One thing prepares 

 the way for another, and an order of succession has been established from the beginning. The 

 kind of plants which the farmer ought to grow, and their order of precedence, should be one 

 of his first lessons. Next to rotation would be mixtmres of different earthy materials, especially 

 those of opposite quality from the soil to be improved, which probably may be one of the 

 causes why change becomes necessary ; and hence a shorter rotation might advantageously 

 be pursued, for the great benefit of this operation may arise from the change which plants 

 produce in soil by excretion, decay of materials, and mechanical action. 



From the great body of well informed practical agriculturists now engaged in improving 

 their soil by earthy mixtures of various kinds, manures, saline materials, and rotation, it is 

 hoped that agriculture, a subject so obscure and yet of such vital importance, will, by the 

 conjoined aid of theorists versed in its practice, take its rank among the exact sciences ; and 

 as it is the basis of civilization, it will in practice be considered among the most ennobling of 

 human pursuits, and become consequently the prime element of education. 



CertJiin earthy mixtures which contain no nutriment, such as the marl of New-Jersey, 

 possess a highly fertilizing quality, the efficient cause of which is as yet unknovra ; for it can 

 not be the potash contained therein, as was formerly supposed, since in that case micaceous 

 or primary soils would be more productive than they are. Too httle attention it seems to 

 me, has hitherto been given to the effects developed by the action of the sun's rays on diffe- 

 rent colored particles in the soil : the whiter particles producing reflection in excess, may give 

 rise to a repellent force ; while the darker colored ones, being less reflective, receive the full 

 influence of the calorific rays, and thereby evolve the elective aflinity, or force of combination. 

 By the assiduous study of the laws of these two forces, which have a close analogy with the 

 powers of life, we would probably do more to remove the difliculty in question, than by fol- 

 lowing any course which has been hitherto pursued. 



No fact is more obvious than the connection generally between rock and soil, and soil and 

 population. Where all things else are the same, the number of inhabitants in all countries 

 where man cultivates the earth, and is unfettered, are in direct proportion to the goodness of 

 the soil. This is exemplified in every part of the district. The best soils are those of the 



