SECT. I. WATER. 



shall consider it under the six following heads : 

 Water, Gases, Vegetable Extracts, Salts, Earths, 

 Manures. 



SECTION I. 

 Water. 



As water is necessary to the commencement of Absorbed 

 vegetation so also is it necessary to its progress. r o t. G 

 Plants will not continue to vegetate unless their 

 roots are supplied with water ; and if they are kept 

 long without it the leaves will droop and become 

 flaccid, and assume a withered appearance. Now 

 this is evidently owing to the loss of water. For if 

 the roots are again well supplied with water the 

 weight of the plant is increased, and its freshness 

 restored. But many plants will grow, and thrive, 

 and effect the developement of all their parts, if the 

 root is merely immersed in water, though not fixed 

 in the soil. Lilies, Hyacinths, and a variety of 

 plants with bulbous roots, may be so reared, and are 

 often to be met with so vegetating ; and many 

 plants will also vegetate though wholly immersed. 

 Most of the marine plants are of this description. 

 It can scarcely be doubted therefore that water 

 serves for the purpose of a vegetable aliment. 



But if plants cannot be made to vegetate without 

 water ; and if they will vegetate, some, when partly 

 immersed without the assistance of soil ; and some 



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