Leaves by the Acre 



Probably no one ever had time and patience, or thouaht 

 it worth while, to measure the I'af surface exposed by the total 

 foliage of a large tree. But one way readily enough measure a few 

 leaves, and make an estimate; and it then appears that the leaf sur- 

 face of a good sized tree must be measured in acres. When we re- 

 flect that the breathing pores are scattered thickly over the under 

 surfaces, and sometimes over the upper surfaces also, of the leaves, 

 and reflect that under normal circumstances each pore is taking in 

 air and giving out moisture, it no longer seems surprising that a tree 

 must send its roots far into the earth in search of water, or that the 

 carbon taken from the air can build up as rapidly as it is observed 

 to do the bulk of the tree trunk. A few leaves spread out together, 

 as in the picture, give one a realizing sense of the way in which the 

 surfaces take up space. Remember, too, that each leaf 

 has a lower surface, doublina thcarea here exposed. 



