44 AMERICAN MANURES. 



acre. These facts need no further comment, 

 and conclusively prove the necessity of adding 

 ammonia or nitrogen, in some form, to the grow- 

 ing plant, to supply this element. 



CHLORINE. 



Chlorine is a yellowish green liquefiable gas, 

 of a pungent, suffocating odor. It is incom- 

 bustible, but supports the combustion of a few 

 bodies. Chlorine is incapable of supporting 

 respiration, causing instantaneous death when 

 inhaled pure ; when diluted with atmospheric 

 air, and breathed in small quantities, it excites 

 violent coughing, accompanied by an oppressive 

 choking sensation, sometimes followed by spitting 

 of blood. 



Chlorine is abundantly found in nature in 

 combination with sodium, as rock salt ; it is also 

 found in sea-water and marine plants. 



The reader will see, by referring to the tables 

 showing the Composition of Plants, that a very 

 small amount of this element is required ; and as 

 it is always applied to the soil in alkaline 

 chlorides, we shall review this element more 

 fully under the head of Sodium. 



The foregoing brief review of the gases that 

 enter into the composition of plants, and the 

 compounds they form with other elements, 

 should be well considered and understood by the 



