64 INORGANIC CONSTITUENTS. 



celved, as those plants which furnish ashes abounding in carbonate 

 of soda, always contain organic acids combined with the alkaline 

 base. Borage, the nettle, &c., thrive only in places where they 

 meet with nitrates ; and it is easy to discover that plants when dried 

 contain a notable quantity of either nitrate of potash or of lime. 

 The vine more especially requires alkaline dressings, in order that 

 the large quantities of potash taken from the soil in the tartrate of 

 potash of the grape may be replaced. 



The organic acids, so different in their composition and in their 

 properties, which are met with in the different vegetable families, 

 are always found combined in the stale of neutral or acid salts. The 

 proportion of base combined in a plant with a vegetable acid may be 

 readily ascertained from the ashes ; for by the effect of incineration 

 the base passes into the state of an alkaline or earthy carbonate. 

 The vegetable acids undoubtedly perform important functions in the 

 organism of vegetables, and their formation probably depends on the 

 influence of the bases with which they form salts. The nature of 

 the oxide or base itself appears to be of little importance ; it is 

 enough that it be present in the plant. It is known that certain bases 

 may mutually replace each other, equivalent for equivalent. 



These principles assumed. Prof. Liebig draws a remarkable in- 

 ference from the composition of the ashes of different kinds of wood ; 

 namely, that for each vegetable family the sum of the oxygen of the 

 bases combined with the organic acids will be a constant number ; 

 or, in other words, the species of one and the same family will con- 

 tain the same number of basic equivalents combined with vegetable 

 acids. 



Thus, 100 parts of the ashes of a Breven pine-tree, analyzed by 

 Saussure, contain : 



Carbonate of potish 3.r>0 Oxygen of the potash 0.411 



lime 40.34 " lime 7.33V9.01ox. 



" magnesia 6.77 " magnesia 1.27) 



Carbonates ^7.56.71 



The ashes of a pine from Mount La Salle yielded : 



Carbonate of pntasli 7.3t> Oxypen of the potash 0-85 J o q^ «- 



lime 51.f.y • lime S-lOp'^"- 



" magnesia 0.(M) 



M. Berthicr found in the ashes of a fir-tree from Allevard the 

 following bases : 



Potash and Soda lfi.8 Oxygen 3.42) 



Mmc 2l>.5 " 8.20V12.82 



Magnesia 3-2 " 120) 



49.5 



One part of the alkalies containintr l.*30 of oxygen was combined 

 with mineral acids, forming sulphates, pliosphates, and a chloride 

 The oxygen of the bases combined with the carbonic acid is conse- 

 quently reduced to 11 6'2. 



The ashes of a Norway fir, according to the same analyst, con- 

 taining : 



