TJie Neglect of Qiemhtrij by Practical Farmers. 441. 



salts of -wliicli they are composed. The case of the analyses made 

 by Mr. Hunt, noticed hi the Essay, will, I think, bear out the 

 above observations. 



At any rate, from the above facts it appears that a large margin 

 must be allowed when consulting any of the quantities given in 

 these tables per acre, as at the best they can only be considered 

 as approximations to the truth, allowance being made for the 

 amount of extraneous water in the soil, as also the state of tilth 

 it might be in. 



It must be borne in mind that it is only the soluble portion 

 that has any present interest to the practical farmer, which leads 

 me to notice a great oversight that chemists have (nearly without 

 exception) committed in their analyses of soils, for the benefit of 

 practical farmers, in merely giving the total amount of the salts 

 that are abundantly soluble m water instead of specifying each 

 individual salt : while, at tlie same time, they have often spared 

 neither time nor trouble in ascertaining the composition of that 

 portion of the soil which was difficultly soluble or insoluble in 

 acids, and which, comparatively speaking, possesses but slight 

 interest to the practical farmer. 



Dr. Daubeny has shown, by some experiments in the Botanical 

 Garden at Oxford, that the amount of ingredients soluble in water 

 that remamed in the soil, after a severe cropping for ten years, 

 without the application of any mianure, was incomparably smaller 

 than that which was present in another portion of the same soil 

 W"hich had not been thus exhausted, while there was no appre- 

 ciable difference in the quantities of the remaming constituents. 

 The theory he deduced from these experiments was, that those 

 salts which are capable of being dissolved by rain vrater are 

 available for the present use of the farmer (these he terms the 

 "active" ing-redients of the soil); that those constituents which 

 require muriatic acid to dissolve them may become serviceable to 

 the farmer at some future time (these he calls " dormant "), whilst 

 the remainder, which he designates as the " passive" ingredients, 

 and which are insoluble in muriatic acid, he considers will never 

 be available to the farmer, for the present generation at least. 

 Knowing these facts — for who can doubt their truth ? — it certainly 

 does seem extraordinary that chemists should have passed over 

 this most important element of their research, and have devoted 

 so much of their time and enero-ies to the investio-ation of that 

 part of the subject which there seems reason to believe will never 

 be of any practical use to the farmer (mind I am speaking here 

 only of agricultural chemists). 



There is one exception only in all the analyses collected in 

 these two tables, and that has been made bv Dr. Richardson, 



2 G 2 



