98 OF THE INORGANIC 



The firwood of Norway contained in 100 parts :* 



Potash . 14-1 of which 2'4 parts would be oxygen. 



Soda . 20-7 5'3 



Lime . 12%3 3'45 



Magnesia . 4-35 ,, 1-69 



51-45 12-84 



And if the quantity of oxygen of the bases in com- 

 bination with sulphuric and phosphoric acid, viz- 

 1* 3 7) be again subtracted from 12*84, 1T47 parts 

 remain as the amount of oxygen contained in the 

 bases, which were in combination with organic 

 acids. 



These remarkable approximations cannot be acci- 

 dental ; and if further examinations confirm them 

 in other kinds of plants, no other explanation than 

 that already given can be adopted. 



It is not known in what form silica, manganese, 

 and oxide of iron, are contained in plants, but we 

 are certain that potash, soda, and magnesia, can be 

 extracted from all parts of their structure in the 

 form of salts of organic acids. The same is the case 

 with lime, when not present as insoluble oxalate of 

 lime. It must here be remembered, that in plants 

 yielding oxalic acid, the acid and potash never exist 

 in the form of a neutral or quadruple salt, but 



* This calculation is exact only in the case where the quantity of 

 ashes is equal in weight for a given quantity of wood ; the difference 

 cannot, however, be admitted to be so great as to change sensibly the 

 above proportions. Berthier has not mentioned the proportion of ashes 

 contained in the wood. 



