530 AGRICULTURAL ANALYSIS 



Unleached I,eached 

 per cent. per cent. 



Insoluble 13.0 13.0 



Moisture 12.0 30.0 



Calcium carbonate and hydroxid 61.0 51.0 



Potassium carbonate 5.5 i.i 



Phosphoric acid 1.9 1.4 



Undetermined 6.6 3.5 



In the wood ashes of commerce, it is evident that the propor- 

 tion of the potash to the lime is relatively low. 



The number of parts by weight of the chief ingredients of the 

 ash in 10,000 pounds of woods of different kinds is given in the 

 table page 531, with the percentage composition of the pure 

 ash, that is the crude ash deprived of carbon and carbon dioxid. 



449. Statement of Results. The bases which are found pres- 

 ent in the ashes of wood and other vegetable tissues exist with- 

 out doubt before incineration, chiefly in combination with in- 

 organic acids. Even the phosphorus and sulfur which after igni- 

 tion appear as phosphates and sulfates, have previous thereto 

 existed in an organic form to a large extent. The silica itself 

 is profoundly modified in the organism of the growing plant, and 

 possibly may not exist there in the purely mineral form in 

 which it is found in the ash. During the progress of incineration, 

 with proper precautions, all the phosphorus and sulfur are oxi- 

 dized and appear as phosphoric and sulfuric acids. The silica is 

 reduced to a mineral state, and if a high heat be employed sili- 

 cates are formed. The organic salts of lime, magnesia and other 

 bases at a low temperature are converted into carbonates, and if 

 a higher temperature be used, may appear as oxids. The organic 

 compounds of alkalies will be found in the ash as carbonates. 

 It would be useless, therefore, to try to state the results of ash 

 analysis in forms of combination similar to those existing in the 

 original vegetable tissues. It is not certain even that we can in 

 all cases judge of the form of combination in which the different 

 constituents exist in the ash itself. It is, therefore, to be pre- 

 ferred in a statement of ash analysis to give the bases in the 

 form of oxids, and the sulfur and phosphorus in the form of an- 

 hydrides, and the chlorin in its elementary state. In this case an 



