174« Prof, H. Rose on the Inorganic Constituents 



ward here, as obtained by the latter defective method. In 

 this case it amounted to r424< grm. from 300 grms. of peas, 

 whilst by the other method 2*726 grms. were obtained. 

 It consisted per cent, of — 



Potash 17-83 



Lime 8*77 



Magnesia .... 20-85 



Peroxide of iron . . 2-24< 



Phosphoric acid . . 46'98 



Silica 1-89 



98-56 



The amount of the potash and phosphoric acid is diminished 

 by the volatilization of the phosphate of potash ; whilst that of 

 the lime, the magnesia, the peroxide of iron, and the silica 

 have been increased. 



The proportion of the phosphoric acid to the bases in the 

 ash of the pea-straw is the same as that in the 6-phosphates. 

 Yet only lime and magnesia could have been combined with 

 the ^'phosphoric acid, since the quantity of this acid found is 

 only sufficient for these bases. If the two earths were con- 

 sidered as Z»-phosphates, 21-60 per cent, phosphoric acid 

 would be required. The considerable quantity of peroxide 

 of iron must not be considered as existing in combination with 

 phosphoric acid in the ash. 



The following are the inorganic constituents contained in 

 the muriatic extract and the incinerated carbonized residue 

 of peas ; they have been added together, because they are 

 sometimes considered as constituting the portions of the ash 

 insoluble in water. 



Potash 32-66 



Soda 2-11 



Lime 6-08 



Magnesia .... 9*91 



Peroxide of iron . . 0*98 



Phosphoric acid . . 4'7'62 



Silica 0-64 



100-00 



We thus see the large amount of alkali contained in those 

 constituents which are insoluble in water, and the presence of 

 which has previously been almost always overlooked. 



The inorn-anic constituents of the muriatic extract and in- 

 cinerated carbonized mass of pea-straw were — 



