EFFECTS OF CHALK ON THE WOLDS. 377 



some measure in the dark, both as to the way in which a dressing of 

 chalk acts in improving a soil already rich in chalk, and why chalk 

 from one locality should act so much more beneficially than another. 



With one thing, however, we are familiar, that the upper beds of 

 chalk abound in flint, and where they form the surface support a thin 

 and scanty herbage — while the under chalks are more tenacious and 

 apparently more rich in clay, and support generally a soil which yields 

 valuable crops of corn. An admixture of the lower, therefore, ought to 

 improve the soils of the upper; and as the chalks of Kent consist of 

 these lower beds, we can understand why the practical farmer in Suf- 

 folk should prefer them to the upper chalks of his own neighbourhood. 

 Still we cannot, as yet, give the scientific reasons why the one chalk 

 should be better than the other. A rigorous chemical analysis can 

 alone determine with certainty why the one should produce a differ- 

 ent effect from the other. 



Chalks may differ in the proportion of clay or of organic matter with 

 wliich they are associated — in the quantity of silica (the substance of 

 flints) or of silicates they contain, — in the amount of magnesia or of 

 phosphate of lime which can be detected in them — or of saline matter 

 wliich a careful examination will discover, — and they may even differ 

 ph3^sically in the fineness of the ultimate particles of which the sub- 

 stance of the chalk is composed.* All such differences may modify 

 the action of the several varieties in such a way as, when accurately 

 investigated, to enable us to account for the remarkable preference 

 manifested by practical men for the one over the other. Until such 

 an investigation has been carefully made, it is unfair hastily to class 

 among local prejudices what may prove to be the results of long prac- 

 tical experience. 



On the chalk Wolds of Lincolnshire and Yorkshire the practice of 

 chalking even the thin soils is now comparatively old in date. The 

 lowest chalks are there also much preferred, — they are laid on at the 

 rate of 60 to 80 cubic yards per acre, and they cause a great improve- 

 ment, especially upon the deep lands, as they are called, where the 

 soil is deepest. Corn does not yield so well, nor ripen so early, on 

 these deep soils, as where a thinner covering rests upon the chalk. It 

 is naturally also unfit for barley or turnips, the latter plant being espe- 

 cially infested with the disease called fingers and toes [British Hus- 

 bandry, iii., p. 124 ] (Strickland). But a heavy chalking removes all 

 the above defects of these deep soils, and for a long period of lime. 

 The corn ripens sooner, is larger in quantity, and better in quality, 

 and the turnips grow perfectly free from disease. 



These, however, are to be regarded as only the usual effects of a large 

 addition of lime to a soil in which previously little existed. It is a 

 fact which will naturally strike you as remarkable, that soils which rest 

 upon chalk, as well as upon other lime-stone rocks, even at the depth 

 of a few inches only, are often, and especially when in a state of nature, 

 so destitute of lime that not a particle can be detected in them^. That 

 lime in any form should benefit such soils is consistent with uniform 



• Ehrenberg has discovered that chalk is in a great measure composed of the skeletoM^ 

 stiells, or other exuvial (spoils) of marine microscopic animals. 



