214 



COMPOSITION Cy THE OXIDES AND CHLORIDES. 



these oxides be dissolved in muriatic acid a solution of chloride of maL- 

 ganese will be obtained. 



If this solution of chloride of manganese be mixed with one of car- 

 bonate of soda, a white insoluble powder will fall, which is carbonate of 

 maganese. 



If this carbonate be dissolved in diluted sulphuric acid, or if any of 

 the oxides be digested in this acid, a solution of sulphate of manganese 

 will be formed. 



The carbonate of manganese, and its oxides, will also dissolve, though 

 more slowly, in acetic acid (vinegar), and in other organic acids which 

 may be present in the soil, and will form with them other soluble 

 salts. 



The compounds of manganese exist in plants in much less quantity 

 than those of iron; but as its oxides, like those of iron, are insoluble in 

 pure water, this metal most hkely finds its way into the state of one 

 or other of the soluble compounds above described. 



§2. 



Tabular view of the constitution of the compounds of the inorganic 

 elements above described. 



Having in the preceding section briefly described the several compounds 

 of the inorganic elements of plants, which either enter into the constitution 

 of vegetable substances, or are supposed to minister to their growth — it 

 may prove useful hereafter, if I exhibit at one view the composition per 

 cent, of the various oxides, chlorides, sulphurets, and oxygen-acid salts,* 

 to which I have had occasion to direct your attention. 



We shall have occasion to refer to the numbers in the following tables 

 in our subsequent calculations. 



1°. — Oxygen per cent, in the oxides of the inorganic elements. 



Oxygen Oxygen 



per cent. per cent. 



. 49-85 Alumina 46-70 



. 59-86 Silica 51-96 



. 56-04 Prot-oxide of Iron . . 22-77 



. 16-95 Per-oxide oflron . . . 30-66 



. 25-58 Prot-oxide of Manganese 22-43 



. 28-09 Sesqui-oxide do. . . 30-25 



. 38-71 Per-oxide do. . . 36-64 



Sulphurous Acid 

 Sulphuric Acid 

 Phosphoric Acid 

 Potash . . . 

 Soda .... 

 Lime . . . 

 Magnesia . . 



2°. — Chlorine or Sulphur per ce'it.dn the chlorides and sulphurets. 



Chloride of Potassium 



Sodium 



Calcium 



Magnesium 



First Chloride of Iron 

 Second do. do. 



Chlorine 

 per cent. 

 47-47 

 60-34 

 63-38 

 73-65 

 56-62 

 66-19 



Sulphuret of Potassium 



Sodium . . 



Calcium . . 



Iron 



Bi-Sulphuret oflron, 

 (Iron Pyrites) . 



Sulphur 

 per cent. 

 29-11 

 40-88 

 44-00 

 37-23 



47-08 



So called because the acid they pontain has oxygen for one of its constitaenta 



