176 Prof. H, Rose on the Inorganic Constituents 



Oxygen. 

 Chloride of potassium . 1*96 

 Chloride of sodium . . 1'83 



Potash 15-68 



Lime 27-14. 



Magnesia 6-50 



Peroxide of iron . . . 1*30 



Phosphoric acid . . . 13-52 



Sulphuric acid . . . 0-57 0-34. I 



Carbonic acid . . . 25*52 18-46 f 



Silica 5-98 



13*18 



26*37 



100-00 



The proportion of the oxygen of the bases to that of the 

 acids in both the peas and the pea-straw is therefore as 1 : 2. 

 The oxygen of the silica in the pea-straw is not added to that 

 of the other acids, because it is not combined with bases in the 

 straw. 



The manner in which the inorganic constituents of organic 

 substances are usually determined, consists in the direct in- 

 cineration of the organic substance, and in arranging the 

 constituents found in the analysis, by uniting the strongest 

 bases with the strongest acids. The carbonic acid in many 

 cases was not determined directly ; and the portion of the 

 bases remaining, after calculating the salts formed by them 

 with the acids found, was assumed as carbonates. The above 

 results show to what very erroneous ideas this method of ar- 

 rangement may lead. On calculating according to the above 

 principle the salts from the numbers quoted last, we should 

 obtain totally different arrangements, or at least totally differ- 

 ent per-centage results from those obtained by the separate 

 exhaustions of the carbonized substance. Thus all the alkali, 

 for instance, in the ash of the peas remaining after calculating 

 the amounts of chloride and alkaline sulphate, would be re- 

 garded as alkaline phosphate. The phosphoric acid then 

 remaining would be combined with other bases, and what 

 remained of the latter would be regarded as combined with 

 carbonic acid. But we have now seen that part of the potash 

 exists in the aqueous solution of the carbonized mass in the 

 state of carbonate, and that in the teleoxidic portion of the 

 carbonized mass the earths extracted by the muriatic acid 

 could only have been combined with phosphoric acid, because 

 no carbonic acid is evolved when an acid is added. 



This principle is seen to be still more erroneous in the de- 

 termination of the inorganic constituents of the pea-straw. 

 No phosphoric acid exists in the aqueous extract of the car- 



