CONSTITUENTS OF PLANTS. 97 



made for the very purpose of ascertaining the fact 

 above demonstrated which the analyst in this case 

 had not in view. 



Let us now compare Berthier's analyses of the 

 ashes of two fir-trees, one of which grew in Nor- 

 way, the other in Allevard (de'partement de llsere). 

 One contained 50, the other 25 per cent, of solu- 

 ble salts. A greater difference in the proportion 

 of the alkaline bases could scarcely exist between 

 two totally different plants, and yet even here, 

 the quantity of oxygen in the bases of both was 

 the same. 



100 parts of the ashes of firwood from Allevard 

 contained according to Berthier, (Ann. de Chim. et 

 de Phys. t. xxxii. p. 248,) 



Potash and Soda 16-8 in which 3-42 parts must be oxygen. 

 Lime . 29'5 8'20 



Magnesia . 3'2 1'20 



49-5 12-82 



Only part of the potash and soda in these ashes 

 was in combination with organic acids, the remain- 

 der was in the form of sulphates, phosphates, and 

 chlorides. One hundred parts of the ashes con- 

 tained 3*1 sulphuric acid, 4*2 phosphoric acid, and 

 0*3 hydrochloric acid, which, together, neutralise a 

 quantity of base containing 1.20 oxygen. This 

 number therefore must be subtracted from 12*82. 

 The remainder 11*62 indicates the quantity of oxy- 

 gen in the alkaline bases, combined with organic 

 acids, in the firwood of Allevard. 



H 



