70 CHYMISTRY APPLIED TO AGRICULTURE. 



If it be required to employ, as manure, some substances, 

 whether animal or vegetable, which are by nature soluble 

 in water, their mixture with lime forms new compounds of 

 natures completely different from their constituent principles, 

 but which may, in time, become very proper for the nutri- 

 ment of plants : this requires some explanation. 



The compounds formed by lime with nearly all the soft 

 animal or vegetable substances which will combine with 

 it, are insoluble in water; accordingly, lime destroys or 

 greatly diminishes the property of fermentation in the 

 larger part of them ; but these same compounds at length 

 undergo a change from being exposed for a length of time to 

 the constant action of air and water ; the lime passing to the 

 state of a carbonate, and the animal and vegetable substances 

 being gradually decomposed, and furnishing new products 

 capable of supplying nourishment to plants; so that lime 

 answers two great purposes for nutriment ; first, it disposes 

 certain insoluble bodies to form by their decomposition solu- 

 ble compounds; and, secondly, it prolongs the -action and 

 nutritive virtue of some soft and insoluble animal and vege- 

 table substances, beyond the term they would continue to 

 act if they were not made to enter into combination with 

 lime. 



Very striking instances of the facts which I have just 

 stated, may be found in some of the operations performed 

 in various branches of manufactures. For instance, in 

 the process of refining sugars to free them from the vege- 

 table extract and the albumen which they contain, the milk 

 of lime is employed, which, combining with these sub- 

 stances, rises to the surface of the liquid in the form of a 

 thick and insoluble foam or scum ; this, if carried immedi- 

 ately into the fields, destroys vegetation, but if deposited in a 

 ditch during a year, it forms one of the most fertilizing 

 manures with which I am acquainted. I have established 

 this fact by having employed, in this manner, during the 

 period of a dozen years, the abundant foam arising from the 

 first operations performed upon the sugar of beets in my 

 manufactory. 



From the explanation which I have given of the manner 

 in which lime acts, we may draw some conclusions in regard 

 to its uses, and to the manner in which it should be em- 

 ployed in order to have the results, arising from its applica- 

 tion, conform to those which have been produced by en- 

 lightened experiments. 



