DR. DAUBENY ON THE ROTATION OP CROPS, ETC. 237 



I next proceed to the flax, which in ten years produced, as we have seen, an 

 amount of crop equal to 126 lbs., yielding of ashes 8*4 lbs. 



of which 1-26 was extraneous. 



Leaving of real ash 7*14, which would consist of — 



Silica 0-520 



Phosphoric acid . . . 0*520 



Sulphuric acid .... 0*264 



Carbonic acid . . . . 1*020 



Chloride of sodium . . 0*099 



Soda ....... 0*490 



Potass . 0*925 



Magnesia 0*390 



Lime . . . . ^ . . . 2*850 



7*078 

 Now the average of ten crops of flax, cultivated in different plots of the same 

 garden, was 22*7 lbs., yielding 1*816 of ashes, = in ten years 18*16 lbs., of which 

 3*36 lbs. were extraneous, leaving 14*8 lbs. of real ash, which would consist of the 

 following ingredients : — 



Silica 0*34 



Phosphoric acid .... 1*25 



Sulphuric acid .... 0*78 



Carbonic acid . . . , 3*22 



Chloride of sodium . . . 0*30 



Soda 0*20 



Potass 3*80 



Magnesia 0*87 



Lime 4*00 



14*76 



The last of the crops made the subject of examination was the beans, where the 

 aggregate of ten years' produce, in the case of the permanent crop, was 247 lbs., 

 which would have yielded 10*8 lbs. of ashes. 



Of this, however, about 1*1 would consist of extraneous matter. 



Leaving 9*7 of real ash, 



consisting of the following ingredients : — 



Silica 0*44 



Phosphoric acid .... 0*36 



Sulphuric acid .... 0*22 



Carbonic acid .... 2*13 



Chloride of sodium . . . 0*12 



Soda 0*76 



Potass 1*37 



Magnesia ...... 0*40 



Lime 3*90 



9*70 

 2 I 2 



