554. 



a sufficient quantity of these ingredients in a state lo be immedi- 

 ately taken up ; the second, that of waiting until the action of de- 

 composing agents disengages a fresh portion of those ingredients 

 from the soil (as by letting the land remain fallow) ; and the third, 

 that of accelerating this decomposition by mechanical and chemical 

 means. 



Thirdly, that it is probable that in most districts a sufficient 

 supply of phosphoric acid and of alkali for the purpose of agricul- 

 ture lies locked up within the bowels of the earth, which might be 

 set at liberty and rendered available by the application of the arti- 

 ficial means above alluded to. 



Fourthly, that the aim of nature seems to be to bring into this 

 soluble, and therefore available condition, these inorganic substances 

 by animal and vegetable decomposition, and therefore that we are 

 counteracting her beneficial efforts when we waste the products of 

 this decomposition by a want of due care in the preservation of the 

 various excrementitious matters at our disposal. 



Fifthly, that although vre cannot deny that plants possess the 

 power of substituting certain mineral ingredients for others, yet that 

 the limits of this faculty are still imperfectly known, and the degree 

 in which their Ivealthy condition is affected by the change is still a 

 matter for further investigation. 



Lastly, that the composition of various plants, as given in this 

 paper, differs so widely from that reported by Sprengel and others, 

 that we are supplied with an additional argument in favour of the 

 importance of having the subject of ash-analysis taken up by a 

 public body, such as the Royal Agricultural Society of .England, 

 possessed of competent means and facilities for deciding between 

 the conflicting authorities, and supplying us with a more secure 

 basis for future calculations. 



I 



May 29, 1845. 



The MARQUIS OF NORTHAMPTON, President, in the Chair. 



" On the Ashes of Wheat." By William Sharp, Esq., F.R.S. 



The experiments recorded in this paper were undertaken princi- 

 pally with the ultimate view of ascertaining with exactness what 

 quantity of inorganic matter is removed from the soil by the seeds 

 of a crop of wheat. The author first inquires what is the average 

 amount of the inorganic or incombustible portion of a given quan- 

 tity of wheat ; a question to which no satisfactory answer has yet 

 been given. The result of the author's experiments is, that wheat 

 yields, by slow combustion, a residue of from 1-| to 1|- per cent. He 

 then proceeds to determine by experiment the degree in which this 

 result is influenced by previous drying at different temperatures, 

 varying from 230° to 260° Fahr., and finds that a heat of 245° is 

 not sufficient to expel all the moisture contained in wheat ; for while 



