124 GENERAL FLUID COMPONENTS. [LECT. III. 



The solids, also, except the earths and salts, 

 are formed from the same principles : 100 parts of 

 the ligneous fibre of the Beech and the Oak, for 

 example, consisting of 



Beech. -Oak. 



Carbon 51.45 . . . . 52.53 

 Oxygen 42.73 .... 41.78 

 Hydrogen 5.82 .... 5.69 



100.00 100.00 * 



and thus almost the whole of vegetable matter 

 may be resolved into these three simple elements. 



Such are the general components of vegetables. 

 The investigation of them is yet in its commence- 

 ment only, and much must be done before their 

 real properties be fully understood. It is requisite 

 that the student keep them constantly in view, 

 for otherwise much of the more detailed part of 

 our subject will appear obscure and confused. 



* Recherches physico-chimiques, t. ii. p. 294. Thomsons 

 Chemistry, fifth edition, vol. iv. p. 183. 



