314 IS NITRIC ACID FOOD FOR PLANTS ? 



The nitrogen of nitric acid, when placed in contact with hydro- 

 gen at the moment of its liberation, as in the solution of tin, or by 

 fusing nitrates with potash and organic substances, is converted 

 into the compound of hydrogen. In all cases in which we expose 

 to a high temperature a body containing nitrogen and caustic 

 potash, its nitrogen assumes the form of ammonia. 



The nitrogen of an organic body, of vegetable or animal mat- 

 ter, or of the charcoal produced from them, arises from the am- 

 monia which the plant contained and abstracted from the atmo- 

 sphere : it enters, in the processes of decomposition alluded to, into 

 its original form, and assumes the condition of ammonia. 



But these instances cannot be cited as proper examples of the 

 formation of ammonia, nor can they be considered with reference 

 to the question which we have now been discussing. 



IS NITRIC ACID FOOD FOR PLANTS? 



Before we can examine the opinion whether nitric acid be a 

 means by which nitrogen is furnished to plants in nature, it is 

 most important to consider the origin of nitric acid. 



At the request of the French Government, the Academy of 

 Sciences of Paris, in the year 1770, offered a prize for the best 

 treatise on the formation of nitric acid and its production in arti- 

 ficial nitre-beds. The judges appointed by the Academy, includ- 

 ing Lavoisier, subjected to trial 70 treatises, the results of which, 

 after the experience of 50 years, were stated in a small work 

 published by Gay Lussac, in the year 1825,* in the following 

 sentences : — 



1. "All the nitrogen necessary for the formation of nitric acid 

 is yielded to it by animal matter." 



2. " Nitre is never generated from the air in substances 



* Instruction sur la fabrication du salpitre, publii par la Commission 

 des poudres et salpitres, 1825 



