30 LIFE OF A TREE. 
end of these experiments shewed two things: 
1. That seeds will not germinate if deprived of 
air;—and 2. That the air in which they germi- 
nate best is that of the atmosphere: that is to 
say, that man cannot by his skill make any ar- 
tificial air or gas which will answer the purpose 
so well as that which the Creator has made. 
The knowledge of the first of these facts ex- 
plains to us how it is that seeds will not grow 
if buried too deep in the earth. How many a 
young florist has been disappointed, after weeks 
of patient watching, weeding, and watering, to 
find his stocks, or his sweet-peas, or his mig- 
nonette, shewing no symptoms of ‘“ coming 
up’! Had he known this simple fact, he would 
never have dug a hole more than half a foot 
deep, and dropped his seeds in, ramming down 
the heavy earth upon their heads. Hence we 
find all gardening-books tell us,—many of them 
perhaps without knowing the reason why, ex- 
cepting from experience,—when we sow our seed, 
to cover it very lightly with earth. Hence also 
the farmer takes care that the furrows shall not 
be too deep on the surface of his field, when the 
corn is about to be committed to its nursing- 
