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DEVOTED TO AGRIOULTaRE AND ITS KINDRED ARTS AND SCIENCES. 



VOL. IX. 



BOSTON, JULY, 1857. 



NO. 7. 



JOEL NOURSE, Proprietor. 

 Office... 13 Commercial Sv. 



SIMON BKOWN, EDITOR. 



FRED'K HOLBROOK, ) Assocutb 

 HENRY F. FRENCH, j Editors. 



JULY-THE VALUE OF ROCKS. 



■ ULY is a busy time 

 with the farmer, 

 and the multitude 

 of his avocations 

 leaves him not ma- 

 ny hours to devote 

 to reading and stu- 

 dy. But as we com- 

 menced the year by 

 devoting a column 

 ^^ , "'^ of our page to the discus- 

 ''^^ jl sion of some useful subject 

 -'(p-' connected with nature, we 

 design at present to make a few com- 

 ments on the value of rocks, as an 

 important agent in the operations of 

 Providence for the benefit of his 

 creatures. The rocks that bound our 

 coasts, and give firmness to the hills and 

 mountains, serve the evident purpose of 

 bulwarks, to preserve the one from crum- 

 bling by the action of the ocean waves, and 

 the other from being washed down to a common 

 level, by the action of rains and the torrents that 

 succeed them. The purposes which ihey serve in 

 these respects are apparent to all ; but we would 

 call attention to the importance of rocks to vegeta- 

 tion, and to the purposes of agriculture. 



If there were no rocks, this globe must pre- 

 sent an even surface in every part ; and were the 

 whole surface one such dead level, it is appar- 

 ent that the strength of the soil would soon be ex- 

 hausted, and that, in order to renovate it, we 

 should be obliged constantly to trench and exca- 

 vate it to great depths, in order to bring up the 

 valuable deposites which had settled below. This 

 labor is saved by the inequalities of the entire sur- 

 face, covered by immense quarries of rocks that 

 protrude above its level. 



From the hills and mountains thus formed, the 

 valleys and plains are constantly supplied with fresh 



deposites of alluvium, occasioned by the crumbling 

 and wear of the surface of these rocks ; the soil is 

 thereby continually renovated, especially when 

 these deposites are increased by a growth of for- 

 ests on these elevations. Every valuable mineral 

 ingredient of the soil has its origin in some one 

 or other species of rocks. The supply which the 

 growth of vegetation demands, may be kept up 

 more or less completely, by the decay of animal 

 and vegetable substances ; but all these would be 

 insufficient, were there no fresh supplies from the 

 rocks that incrust the earth. These hard substan- 

 ces crumble and decay very slowly, and their de- 

 composition is hastened by the growth of trees and 

 other plants. The soil of the valleys is thus per- 

 petually reinforced, and their surface preserved in 

 a constant state of fertility. 



In an essay of this description, we can hardly 

 avoid repeating many common-place and self-evi- 

 dent truths,* but it is always useful and instructive 

 to study the relations that exist between all the 

 difierent objects of creation. The hiore clearly we 

 comprehend these relations, the more lively will 

 be our sense of the wisdom of the Author; and the 

 repetition, even of self-evident truths, may occa- 

 sionally be useful. The work that is done on a 

 large scale by the rocks of our mountains and hills, 

 is done on an inferior scale, by tJie small rocks 

 that lie upon the surface of our fields. There is 

 not a pebble on the surface of the ground that does 

 not contain several important elements of a fertile 

 soil. Granite, it is true, is not so rich in these in- 

 gredients as basalt or limestone and many other 

 rocks, neither is it so easily decomposed ; but it is 

 still an important fertilizer ; and its decomposition 

 is constantly taking place. Hence, however slow 

 this operation may be, yet considering the enor- 

 mous quantities of these rocks, the aggregate of 

 the deposites made by their decomposition must 

 be immense. 



Let us consider for a moment the means which 

 nature has instituted to effect this decomposition. 

 Foremost among them we recognize the rains and 



