152 BY NATURAL DECAY IT IS FINALLY RESOLVED 



extent, and let us consider what becomes of the remainder of the vegeta 

 ble matter. 

 1°. If we add 



6 of Carbonic Acii . . = Cg O12 



to 6 of Light Carburetted ? n u 



Hydrogen (CHo) ^ " ^^ «i2 



we have the sum . . =Ci2Hi2 0i2? or, one of 

 grape sugar; — that is, one of grape sugar may be formed out of the ele- 

 ments of 6 of carbonic acid, and 6 of light carburetted hydrogen. Or, 

 conversely, grape sugar being already produced, it may be resolved or 

 decomposed into these two compounds in the same proportions, without 

 the aid of the oxygen of the atmosphere. 

 2°. So if to 



1 of Woody Fibre = C12 H3 O3 

 we add 4 of Water . . = H4 O4 



Carbonic Light Carbu- 



Acid. retted Hydrogen, 

 we have, as before, C12 H12 C)i2 = 6CO2 + 6 CH2; 

 Or by the aid of the elements of 4 atoms of water, woody fibre may be 

 resolved into 6 of carbonic acid and as many of light carburetted 

 hydrogen. 



3°. Again, in the case of a vegetable acid, if to 



1 of Tartaric Acid = C4 Hg O5 

 we add 1 of Oxygen . . == Oj 



Carbonic Light Carbu- 



Acid. retted Hydrogen. 



we have C^ H2 Og = 3 CO2 + CH2 ; 

 That is, by the aid of one of oxygen from the air, one of tartaric acid 

 may be resolved into 3 of carbonic acid, and 1 of light carburetted 

 liydrogen. It is easy to see how any other of the more common vegeta- 

 ble productions may — either at the expense of its own elements, as in 

 grape sugar— or by the aid of those of water, as in woody fibre — or of 

 the oxygen of the atmosphere, as in tartaric acid — be resolved into car- 

 bonic acid and light carburetted hydrogen, in certain proportions. 



Now, such a resolution does really take place to a considerable extent 

 in nature, during the decay of organic substances in moist situations. 

 Hence the evolution of light carburetted hydrogen from dead vegetable 

 matter in marshy places and stagnant pools — hence the production of 

 the same gas in compost heaps, and especially in rich and heated farm- 

 yard manure — and hence also its occurrence in such vast quantities in 

 many of our coal mines. 



You will now be able to appreciate one of the reasons why this light 

 carburetted hydrogen has been supposed by some physiologists (p. 50) 

 to contribute as food to the ordinary nourishment of plants. It is pro- 

 duced in nature in many and varied situations, and it has been found 

 by experiment to exercise a visible influence upon the growth of plants; 

 — being so produced where young plants grow, is it never imbibed by 

 them 1 — being possessed of this influence, is it entrusted with no control 

 over the general vegetation of the globe ? 



However this may be, by far the greatest portion of both these gases 

 escapes into the air ; — the carbonic acid to fulfil those purposes which 



