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beneficial changes, which deepening and pulverizing effect 

 in soils, according to the ingenious researches of Davy, 

 Thomson, Griesenthwaite, and others, who have usefully 

 laboured to render chemical researches subservient to rural 

 purposes. Had Tull, who flourished about a century ago 

 been acquainted with chemistry, as at present improved, he 

 would not have missed that permanent fame, to w4iich his 

 ingenuity so well entitled him. Tull was unquestionably 

 the first practical advocate for the powers of pulverization ; 

 but he was deceived by its astonishing and various effects, 

 Avithout being able to perceive its limits. Hence he w^as led 

 into the erroneous belief, that pulverization could even supply 

 the place of manures, in farm management. Modern science, 

 however, would have enabled him to discover, that, although 

 the comminuating of soils incredibly multiplies the fibrous 

 roots, or mouths of plants ; although it also facilitates the 

 speedy and perfect preparation of their food, and conducts the 

 food so prepared more regularly to the roots, yet of food itself 

 it does not communicate the smallest supply or portion, beyond 

 w'hat the soil actually possesses. As we cannot, in these times, 

 fall into the error of Tull, let us not omit, for our present pur- 

 pose, to put a due value on pulverization (which in husbandry 

 of late, as connected with deepening, seems to be rather un- 

 dervalued), while we endeavour, by the methods already 

 pointed out, to add as much as possible to the vigour and 

 food of woody plants. 



Soils, then, may be most effectually improved by the plan- 

 ter, by altering their constituent parts, as has been above 

 shown, either by the addition of ingredients, in which they 

 are deficient, or by the subtraction of others, that too much 

 abound in them ; but in ordinary cases, chiefly in the former 

 way, by admixture with other soils, and by the application 

 of mineral manures. The best natural soils are certainly 

 those, of which the materials have been derived from different 

 strata ; that have been, minutely divided by air and water, 



