238 DR. DAUBENY ON THE ROTATION OF CROPS, ETC. 



In the case of the shifting crop of beans the produce of ten years gives an aggre- 

 gate of 336 lbs., yielding of ash 19*15 lbs., 



of which, however, about 2*30 was extraneous, 



leaving 16*85 of real ash, 

 which would contain, of — 



Silica ...... 0*757 



Phosphoric acid . . . 0*723 



Sulphuric acid .... 0*470 



Carbonic acid .... 3*500 



Chloride of sodium . . 0*235 



Soda 0-044 



Potass 3*900 



Magnesia 0*725 



Lime 6*420 



16-774 



Diagram showing the relation between the Permanent and the Shifting Crops. 



The shiftiDK J Potatoes, Barley, | 

 «^««e 1 Turnips, Hemp, > 

 crops. ^ Ylax and Beans . . J 



The 



permanent - 



crops. 



Before we proceed to inquire, whether the difference in the average amount of pro- 

 duce obtained under these two modes of cultivation arose from a deficiency of the 

 organic, or of the inorganic materials present in the soil, it may be worth while to 

 present a tabular view of the numerical relation subsisting between the permanent 

 and shifting crops in each instance, with respect to the entire crop, to the entire 

 amount of inorganic matter, and to the proportions of phosphoric acid and of alkalies 

 present in each. 



