258 HARMONIES OF VEGETATION. 



wiil not take place in azotic ga, in carbonic acid-gas, nor in hy- 

 drogen gas. 



12. From these paragraphs on germination, we learn 

 how nature has suited the seed to the circumstances 

 necessary for its vegetation, and the requisite application 

 of foreign agents to complete the process. 



The first thin? we have obserred necessary, was the maturity of 

 the seed ; next the disposing of the seed in a proper situation, where 

 through the influence of heat, moisture and air, its structure might 

 be acted upon, and its vital principle called into exertion. The first 

 change, is the softening and alteration of its substance ; the cotyle- 

 dons swell, and become seminal leaves, the radicle is sent oat, and 

 nourished with the juices of these leaves until it is sufficiently strong 

 to absorb nutriment from the earth ; then the plumelet begins to 

 ascend, and when the new plant has acquired sufficient strength, the 

 seminal leaves are exhausted of their nonrishingfluids and die, being 

 no longer required. 



FOOD OF PLANTS. 



13. The new plant being produced as described in 

 the last essay, we shall now endeavour to show how 

 nature has provided to support the new individual. 



14. The same agents which were mentioned as neces- 

 sary to give life to the embryo, are also requisite to 

 assist the plant in all its stages of economy. We must 

 therefore say, the food requisite to continne vegetable 

 life, is derived, conjointly from the earth and atmosphere. 



The earth or soil, in general, may be regarded as consisting of 

 diflerent earths, water, salts, and other substances, from which the 

 cot can absorb nourishment. The atrafphcre has bean found to 



