359 



this has been observed by the Rev. W. Thorp, of Womersley, 

 who attributed the failure of the crop to the lightness of the 

 soil. He found a cubic foot of soil, taken from places where 

 the clover failed, always weighed less than one taken from 

 places w^here it came to maturity. Now I imagine this differ- 

 ence in weight would be owing to the quantity of finely divided 

 matter which existed between the coarse particles ; hence we 

 are at once able to attribute the cause of the failure, not 

 simply to the mechanical effect of lightness, but to the small 

 quantity of potash which is rendered soluble in consequence 

 of the size of the particles. If this be the true cause of 

 the failure, we can then understand why a chemical analysis 

 shows the same quantity of potash in soil where clover fails 

 as where it succeeds, for without a mechanical analysis, with- 

 out showing the quantity of those minutely divided matters 

 which are most capable of disintegration, it would be entirely 

 useless. With a view, therefore, to set this matter at rest, 

 I had recourse to the simple method of mechanical analysis 

 recommended by the late Mr. Ram. I separated the fine 

 particles from the coarse sand by agitation with water. In 

 the soil where the clover came to perfection we had coarse 

 sand, 78.6; fine ditto, 21.4. The soil where the plant died 

 away, coarse sand, 81.5; fine ditto, 18.5; in this case, there- 

 fore, we have a quantity of fine sand sufficient to make an 

 appreciable difference on the amount of disintegration in 

 favour of the succeeding piece, and this, with the additional 

 means of effecting its decomposition, will certainly account 

 for the increase of soluble potash. 



Now let us inquire what quantity of potash is required for 

 the development of the clover crop. The analysis shows that 

 10,000 parts, dried in the air, contain 58 parts of potash; 

 hence two tons, the produce of one acre, would require about 

 26 lbs.; now the analysis of the portion where the plant failed 

 contained less than this, although it had been subjected to 



