30 CHEMICAL PHENOMENA, ETC. 



0.324 of a grain of carbon -fO.432 of a grain of oxygen represent 

 0.756 of a grain of carbonic oxide ; 0.030 of a grain of hydro^ajn 

 would require 0.247 of a grain of oxygen to form water. Now, the 

 oxygen remaining, abstraction made of that which enters into the 

 formation of the carbonic oxide is 0.282 of a grain. 



In the first period of its germination, therefore wheat, like trefoil 

 seed, experiences a loss which may in great part be referred to 

 elimination of the carbonic oxide. The chemical composition of 

 these two kinds of seed at more advanced periods of their germina- 

 tion, no longer presents relations so simple. We easily discover 

 that carbon continues to be eliminated ; but the loss no longer cor- 

 responds with that which the oxygen of the seed ought to suffer, in 

 order that the total loss should be represented by a definite compound 

 of carbon. The phenomenon, in fact, becomes extremely complex ; 

 and we can even perceive that it must be so, when we reflect that 

 in proportion as the green parts are evolved, a new chemical action 

 is set up entirely different from that which takes place in the earliest 

 periods of the germination : the green matter of vegetables having, 

 as we shall find, the singular faculty of decomposing carbonic acid 

 gas, and assimilating its carbon under the agency of light. 



This action of the green matter begins to be manifested long be- 

 fore the first phases of germination have entirely ceased ; so that 

 during a certain time two opposite forces are at work simultaneously. 

 One of these, as we have seen, tends to discharge carbon from the 

 seed ; the other tends to accumulate this element within it. So long 

 as the first of these forces predominates, the seed loses carbon ; but 

 with the appearance of the green matter the young plant recovers 

 a portion of this principle ; finally, when by the progress of the vege- 

 tation, the second force surpasses the first in energy, the plant grows, 

 increases, and advances to maturity. 



The presence of light is indispensable to the manifestation of the 

 chemical force by which the green parts of plants appropriate the 

 gaseous elements of the atmosphere. Germination, on the contra- 

 ry, may take place in absolute darkness ; and it would be curious to 

 inquire into the issues of vegetation begiin and ended under such cir- 

 cumstances, in which the organs produced by the seed would have 

 no power to fix any of the principles of the atmosphere to repair the 

 loss of carbon which the seed suffers. It is evident that this loss of 

 carbon must have a limit, which is probably that of germination. 



CONTINUED GERMINATION OP PEAS 



Ten peas, weighing together 2.237 grms. or 34.534 grs. troy, 

 taken as quite dry, were put to germinate in a dusky room, the tem- 

 perature of which was maintained between 12° and 17° cent. (54* 

 and G3° Fahr.) The experiment, begun the 5th of May, was ended 

 on the 1st of July. 



The germinated peas, when dried, weighed 1.075 grm. or 16.595 

 I IS. troy. 



