428 Report on the Exhibition and Trial of Imj)lcmcnts 



change of character in the mechanical structure of such soils, but 

 (in analogy with the effects of drainage) enables the adoption 

 upon them of a SYSTEM of agriculture, to which under horse- 

 power they were before entirely negative. If this be true, — and 

 the practice of Mr. Smith of Woolston seems to have suggested, 

 if it have not established it in the case of his own soil, it is a step 

 in advance, of far higher character and emprise than any derived 

 from a mere comparison of mechanical results upon a trial- field 

 during the exhibition of a week. 



No stronger evidence of the unsuitability of horse-work on 

 clay soils could be adduced than the assertion often heard, on 

 such soils, that tioo years mischief has been done in cases where, 

 from carting over, or ploughing, at improper seasons, the soil has 

 been kneaded and tempered to an unusual degree. A system of 

 culture which permanently excludes the compression of the tread 

 year after year, and leaves such soils open and porous to the 

 highest degree they will admit of, offers a benefit, which it is 

 hardly rating too high to compare with the introduction of turnip 

 husbandly and the tread of the sheepfold upon sandy and other 

 light soils subject to the opposite evil of too great porosity. 



All who are best acquainted with the peculiar characteristics 

 and temper of what are called " sticky soils " (not due to clay 

 alone) are aware that, to a degree which in their case can hardly 

 be over-stated, the true cultivator and best agent of all me- 

 chanical amelioration is the Atmosphere. No cleavage by arti- 

 ficial means can approach its power of comminution and separa- 

 tion, or insure that permanence of lightened texture, by the burst- 

 ing action from within which follows its effectual exposure in 

 the coarsest form to the natui-al solvents, not of the winter's frost 

 alone, but of every season in its turn. Compression from ^the 

 treading of the team, or other causes, even in summer, when it 

 seems most innocent, with its powdering operation upon the sur- 

 face, is a specific violation of the only form of contract with Art 

 or Nature under which such soils will develop their best qualities, 

 in giving full action to the manure, and yielding the largest 

 artificial produce. Even when ploughed by steam, where no 

 compression is inflicted except that necessitated from below in the 

 uptearing of the furrow-slice, there is compression sufficient to con- 

 tract internally, as well as to glaze superficially, the stubborn mass, 

 which, if not by every means coaxed to the utmost freedom and 

 porosity, "saddens'-' in the opposite direction only too readily. 

 Hence one of the reasons why such land when laid down to 

 pasture is so long before it attains to a free and healthy turf; yet 

 in process of time, if laid down in good heart, it does attain its 

 proper mechanical condition, and then produces valuable herb- 

 age that develops its high chemical qualities. That the steam 



