184 



ESSAY XIII. 



effects as the lixivium of Sec. in. (d). The air separated 

 during this detonation was also collected. It appeared to 

 consist of three parts of aerial acid and one part of foul or 

 corrupted air. Hence I conclude that this residuum of 

 cast-iron is plumbago ; but as less nitre is requisite for its 

 decomposition than for the decomposition of plumbago, it 

 must contain less phlogiston than that substance. 



