60 ORIGIN AND 



thus forming ammonia, enters largely into the 

 composition of vegetable gluten, and that this 

 compound is invariably evolved in the decom- 

 position of animal matter. 



Ammonia is farther the simplest of all the 

 compounds of nitrogen and hydrogen, and un- 

 der all circumstances, when these two gases 

 are disengaged in contact, the one with the 

 other, they unite together to form ammonia. 



As all animal matter consists principally of 

 nitrogen, it must therefore in its decay yield it 

 again (combined with hydrogen in the state 

 of ammonia) to the atmosphere, and when the 

 vast amount of animal matter which is con- 

 stantly in a state of decay is considered, our 

 wonder at the source of its supply will cease. 



The ammonia thus liberated or formed by 

 the decomposition of animal matter enters the 

 atmosphere in a gaseous state, which com- 

 bining with the carbonic acid gas, which, as 

 exemplified in the preceding chapter exists 

 also abundantly in the air, forms carbonate of 

 ammonia. 



Ammonia in its gaseous form, as well as in 

 all its compounds with carbon, is exceedingly 

 soluble in water; hence, it cannot long remain 

 in the atmosphere, but must be dissolved and 

 carried into the earth by the first rain which 

 falls after it is evolved. — Hence also rain water 

 must at all times contain ammonia, though 

 not always in equal quantities. It must be 

 greater in summer than in winter, from the 

 double cause, that the showers are more rare 

 in the former case than in the latter, and also 



