ON MANURES. I43 



much stronger, it will probably have the effect of consuming 

 the earth to ashes, in the qualities of which no perceptible 

 difference will be found. In the latter state, indeed, we are 

 strongly of opinion that its effects are purely mechanical — 

 acting upon heavy soils me^ly by correcting their tenacity, 

 and rendering them less stubborn ; but this will doubtless con- 

 tribute greatly to their fertility, though it cannot be considered - 

 as a nutritive manure. 



The stress which has been laid upon the supposed value of 

 some kinds of burned clay, in consequence of the calcareous 

 matter contained in the subsoil, is probably overrated ; for it is 

 seldom found, in soils of that description, in such abundance 

 as to be of much service as a manure to other lands. We 

 learn, indeed, from an experiment of General Beatson, that 

 when even the surface soil has been burned, no difference was 

 found between the effects of that, although containing vegeta- 

 tive matter in the sward, and the ashes of common clay; 

 though the quantity applied was perhaps too small to warrant 

 any positive conclusion. We, therefore, think that the ideas 

 which have been entertained of the effects of this manure, 

 are rather too sanguine; and we are decidedly of opinion that 

 the expectations of those of its advocates who imagine that 

 'burnt clay will supersede the dung-cart' will be disappointed. 

 It appears, indeed, from a more recent essay by Mr, Bur- 

 roughs, on the cultivation of white crops, that he has not been 

 so well satisfied of its good effects as to persist in its use 

 instead of farm-yard manure; for although we there find him 

 recommending the use of the latter, he yet makes no allusion 

 to burned clay. In Scotland, also, where the burning of clay 

 was a few years ago very extensively practised, we learn that 

 it has since fallen into considerable disuse. There can, how- 

 ever, be no doubt that clay ashes may be beneficially used ; but 

 it does not appear from past experience that they can preclude 

 the use of lime on soils not formerly dressed with it. 



We make no apology for the length of these extracts, for 

 the subject is of great importance, and although we entertain 

 doubts of the accuracy of the inferences drawn from the experi- 

 ments by some writers, yet that should not prevent any farmer 

 who possesses the means, of satisfying himself by similar trials, 

 from ascertaining their effect by actual practice. It is true, 

 that the nature of some soils does not admit of it; in others, 

 the land is in many cases so valuable, that almost every inch 

 of it is in profitable use; and as it requires about 150 square 

 ivi 2 



