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



This discrepancy made me desirous of learning, whether, in accordance with the 

 observations of Will and Fresknius, any marked variation in the character of the 

 alkaline constituent might subsist between barley cultivated in an inland county like 

 Oxfordshire, and near the sea, and I therefore procured, through the kindness of a 

 friend one sample from the coast of Essex, and another from that of Cardigansiiire, 

 in South Wales. 



The following were the results obtained of barley from the sea coast of Essex : — 

 1000 grains yielded 19 grains of ash. 

 100 grains of this ash contains, of — 

 Sand and charcoal, extraneous . 23*28 

 Peroxide of iron, extraneous . 2*44 



2572 



Silica 24*89, or, excluding extraneous matter 34*0 



Phosphoric acid 21*84, or, excluding extraneous matter 29*7 



Sulphuric acid 1 *79, or, excluding extraneous matter 2*4 



Carbonic acid ...... 0*00 0*0 



Chloride of sodium .... 0*00, there being no chlorine in the ash. 



Soda . . . . . . . . . 1*05, or, excluding extraneous matter 1*3 



Potass. 15*42, or, exchiding extraneous matter 21*1 



Magnesia 5*29, or, excluding extraneous matter 7'2 



Lime . . 3*36, or, excluding extraneous matter 4*5 



99*36 100*2 



25*72 



Real ingredients of plant . . 73*64 

 Barley-straw belonging to the same crop from Essex. 

 1000 grains yielded 49 grains of ash. 

 100 grains of these ashes contain, of — 



Sand and charcoal, extraneous 8*59 



Peroxide of iron, extraneous . 4*26 



12*85 



Silica . 41*81, or, excluding extraneous matter 48*9 



Phosphoric acid 4*18, or, excluding extraneous matter 4*9 



Sulphuric acid ..... 0*67^ or, excluding extraneous matter 0*8 



Carbonic acid 000 0*0 



Chloride of sodium . . . . 9*58, or, excluding extraneous matter 11*2 



Soda . 0*65, or, excluding extraneous matter 0*7 



Potass 18*49, or, excluding extraneous matter 21*6 



Magnesia 4*95, or, excluding extraneous matter 5*7 



Lime 5*18, or, excluding extraneous matter 6*1 



98*36 99*9 



12-85 



Real ingredients .... 85*5 1 



