1869.] Notices of Scientific Worhs. 407 



on corn and straw, and wo ourselves consume much wheat and 

 other grain. In these instances, although the vegetable substances 

 do not, strictly speaking, decay, yet they undergo another form of 

 the process of oxidation by which burnt charcoal is produced. . . . 

 In this case, the carboD, instead of having been burnt in a furnace, 

 has simply been burnt in our bodies, thereby rendering them warDi, 

 just as when it is burnt in the fire it warms a room." 



Kespecting the unburning of carbonic gas the author illustrates 

 the phenomena of growth and vegetation in the following words, 

 which, whilst they place this subject in a clearer light than we 

 have ever before seen, show at the same time how intimately the 

 conservation of force is bound up with the conservation of matter. 

 " If the sun, instead of shining on the plants which grow on the 

 earth's surface, were to shine entirely upon the stones, it would 

 heat the atmosphere a great deal more than it does. As it is, a 



fortion of the sun's heat disappears. "What then becomes of it? 

 t is absorbed by the vegetation. The amount of heat absorbed by a 

 growing piece of wood in unburning the carbonic gas of the atmo- 

 sphere into charcoal and oxygen is exactly the amount which the 

 piece of wood is capable of giving out when its carbon is reburned 

 in the au*; and accordingly when we burn coals or wood or peat 

 upon our fires, or consume bread and oil and wine in our bodies, 

 and thereby produce a considerable amount of heat either in the 

 fires or in our bodies, we are really manifesting once more in the 

 form of heat, the sun's rays which years and years before shone 

 upon the plants from which those substances were derived." 



When we remind our readers that the chemistry of carbon 

 includes the chemical history of all animal and vegetable substances, 

 it is evident that there can be no better introduction to the study of 

 that grand science for a youth whose tastes he in that direction 

 than the careful perusal of Dr. Odling's Lectures on the Changes of 

 Carbon. 



