RELATIVE AMOUNTS OF AMMONIA. 21 



7. Two additional bell-jars without soil may be added to 

 the series to show the amount of carbon dioxid furnished 

 by the air. This amount is to be subtracted from that found 

 in each of the other bell-jars. 



8. From the amounts of carbon dioxid and ammonia 

 found calculate the relative oxidation of the carbon and 

 nitrogen in the materials. 



9. If desired, corresponding soil portions, kept under 

 the same conditions outside of bell-jars, may be used for 

 determining the daily production of ammonia. This would 

 require ten additional portions with dried blood and ten 

 additional portions with cottonseed meal. 



