216 PICTURING MIRACLES 



pounds. The tree meanwhile had gained one hun- 

 dred and sixty-four pounds, not counting the fallen 

 leaves. As the weight of the soil was almost the same 

 as at the beginning of his experiment, Van Helmod 

 contended that having added nothing 4)ut water, all 

 the increased weight was due to water and to no 

 other media. This experiment may be done by any- 

 one of equal patience and might lead to the same 

 conclusion, but if he would dry the tree, he would 

 diminish its weight by about half; if he would then 

 burn this dried tree a still greater residue would 

 have disappeared in gases, leaving but a small part 

 as ash. 



Later investigators concluded that the weight 

 which had been dissipated from the plant by heat 

 might have been taken in from the air, which theory 

 has been proven. The leaf, through its many mouths, 

 or stomata, often over fifty thousand of them to a 

 square inch, takes in a constant stream of air, from 

 which it separates out carbon dioxide, and that gas, 

 in the leaf, getting its power from the action of the 

 sun thereon, enables it to combine with the plant's 

 sap, producing minute portions of chemicals in the 

 sap, with starch and sugar; this process is known as 

 Photosynthesis. From this most complicated combi- 

 nation the plant is enabled to produce the enormous 

 amount of its own, and in turn, our food. Just how 



