38 Prof. Henry on the Conservation of Force. 
were, locked up in the plant so long as it continues to grow; but 
when it has reached its term of months or years, and some con- 
dition has been introduced which interferes with the balance of 
forces, then a reverse process commences, the plant begins to 
decay, the complex organic molecules begin to run down into 
simpler groups, and then again into carbonic acid and water. 
The materials of the plant fall back into the same combinations 
from which they were originally drawn, and the solid carbon is 
returned in the form of a gas to the atmosphere, whence it was 
taken. Now, the power which is given out in the whole descent, is, 
according to the dynamic theory, just equivalent to the power ex- 
pended by the impulse from the sun in elevating the atoms to the 
unstable condition of the organic molecules. If this power is giv- 
en out in the form of vibrations of the ethereal medium constitut- 
and in this case, as in that we have previously considered, the 
impulse from the sun merely lingers for a while upon the earth, 
through stellar space, until it meets planets of other systems; 
but to attempt to trace it further would be to transcend the limits 
of inductive reason, and to enter those of unbridled fanc 
In the process we have described, the carbon, hydrogen, and 
b 
