588 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



balance one another. The study of the results given below confirms 

 these inferences. The following table is arranged according to the 

 amount of nitrogen present in the oxygen at the time of burning ; 

 it contains the results of all the combustions except the rejected 

 preliminary ones. 



It is seen at once, from the averages in the right-hand column, that 

 an increasing amount of nitrogen decreases the heat of combustion 

 to an extent far beyond the limit of accidental error. In this respect 

 the results with benzol are very different from those with sugar, which 

 has previously been shown to be unaffected by the presence of much 

 nitrogen. The nature of the gaseous or liquid uuburut residue in the 



