94. THE LIFE OF A TREE. 
accompany the mere change of colour in the 
autumnal-tinted leaves. Mr. Hunt, whose name 
we have before mentioned, is inclined to believe, 
that the chemical influence of the sun’s rays 
is modified or altered at this period of the year. 
The change in colour of the leaves is, perhaps, 
due to their absorbing oxygen gas, which they 
will do in the dark and in other circumstances, 
For example, if we expose dried green leaves to 
the action of oxygen gas in a glass jar, and 
moisten them with a little water, they rapidly 
change colour and assume something of the 
Autumn tint. Hence we may suppose, that the 
exciting power of the chemical rays of the sun, 
being less in Autumn than in Spring and Summer, 
renders the leaves less able to resist the action 
of this gas; and the consequence is, that even 
while on the tree they feel its effects nearly as 
much as if they were already dead and dried,— 
and thus the change of colour is produced. This, 
however, may perhaps be too abstruse a subject 
for the general reader, and we must pass on to 
ask :— 
Why does the leaf fall? A great number of 
talented men have endeavoured to give different 
