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MANURES 



Sect. X. 3 



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volatile alkali, as afferted in the ingenious work of Lord Dundonald 



the Conne6lion of Agriculture with Chemidry 



Th 



of th 



mofpl 



hen air is confined in th 



ftices of the foil newly turned over by the plough or fpade, contributes 

 to the production of the nitrous acid by its union with the oxygen of 

 the atmofphere, with which it was before only diffufed, or with the 

 much greater fource of oxygen from the decompofing water of the 

 foil. At the fame time another part of the abundant azote combines 

 v/ith the hydrogen of the decompofing water of the foil, and prod 

 ammonia or volatile alkali ; which contributes to the growth of 

 getables many wavs. as 



3 



ay 



eady defcribed in No. 2. 6. of this S 



tion. 



III. 



WATER. 



pea 



The necelTity of much water in the progrefs of vegetation ap 



from 



quantity, which exifts naturally 



parts of 



plants ; infomuch that many roots, as fquill and rhubarb, are known 



lofe about fix parts out of feven of 



1 



ht fimply by 



drying them before the fire ; which quantity of moifture neverthelefs 

 does not exhale in the common heat of the atmofphere durino- th 

 life of the root ; as is feen m the growth of fquills in the fhops of th 

 druggifls, and of onions on the floors of our flore-rooms 



A fecond neceffity of much 



1 



the economy of 



may be deduced from the great perfpiration of plants, which appea 

 from the experiments of Hales and others ; 

 eflimjated the quantity of their perfpiration 



who like Sandorius h 



from th 



& 



h 



hich h 



daily lofs of 



wever is 



fion eith 



fpca to plants or animals, as they both abforb moiilure from the at- 

 mofphere, as well as perfpire it. 



This great perfpiration of vegetables, like that from the fkin and 



b 



of animals, d 



ppear to confifl of 



mat 



becaufe it has in general no putrefcent fmell or tafte ; but feems 



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to 



