80 LIFE OF A TREE. 
as to produce a firm and solid substance like 
wood again, he is altogether powerless. A blade 
of grass, or the youngest and tenderest leaf of 
the forest, is immeasurably his superior in this 
as in all its other proper chemical processes. 
Now we are prepared to approach this beau- 
tiful page of vegetable history in the right man- 
ner. We have been shewn that the source of 
wood lies not in the soil, nor in the heaven-fall- 
ing rain, but in the wide expanse of our envelop- 
ing atmosphere. And that the minute portion 
of carbonic-acid gas in the air is the ingredient 
from which it is derived. The question now pre- 
sents itself—How is this singular decomposition 
effected? Knowing the 
source of wood, shew 
us the manner in which 
it is obtained.—This we 
shall proceed to do. 
Suppose we pour a 
little carbonic-acid gas 
—7 into a glass jar, at the 
EXPERIMENT oe A SPRIG bottom of which is o 
OF MINT. little saucer full ‘of 
water, and then drop a sprig of growing 
