42 Farmyard Manure. 



cient in lime. Perhaps it may not even contain sufficient to 

 supply the wants of some crops, and seems to be endowed with 

 the property of absorbing lime from manuring matters, affording 

 thereby an interesting instance how special provision is made in 

 soils for the absorption of those constituents which are naturally 

 deficient in them, and which are required in considerable quan- 

 tities for the healthy and luxuriant growth of our crops. 



In the preceding experiment just the opposite took place ; for 

 it will be remembered that the drainings, after passing through 

 the calcareous clay soil, contained a great deal more of lime than 

 before filtration. Similar differences will be observed with 

 respect to other constituents originally present in the liquid and 

 retained in the stiff and in the sandy soil in very different pro- 

 portions. I abstain from noticing any minor changes in the 

 composition of the filtered liquid, nor shall I indulge in any 

 speculations respecting the compounds in the soil which have 

 contributed to these changes and the new combinations in the soil 

 which may have resulted from them. Our present knowledge 

 on the subject is far too imperfect to warrant us to theorise pro- 

 fitably on these matters ; I therefore prefer to send forth for the 

 present my analytical results without any further comment, and 

 conclude by expressing the hope that I may be permitted to con- 

 tinue similar inquiries into the physiology of soils, and do not 

 doubt that great and important practical benefits will in due 

 course be derived from increased knowledge of the properties of 

 soils and the changes manuring matters undergo when in contact 

 with them. 



Royal Agricultural College, Cirencester, 

 June, 1857. 



