78 ESSAY V. 



has all the properties of pure manganese. Here it evidently 

 appears that the air contained in the water is sufficient to 

 attract the phlogiston of the manganese as soon as it is 

 separated from the acid. For the same reason, manganese 

 precipitated from its solution by lime-water is brown ; but 

 on adding more of a concentrated solution of manganese, and 

 afterwards some caustic alkali, the precipitate is white ; 

 because the air contained in the water, being already 

 saturated with phlogiston, is not able to combine with any 

 more. 



(5) On distilling li oz. of phlogisticated manganese 

 in a glass retort with a strong fire, a great quantity of 

 aerial acid, with some drops of water, came over. The retort 

 being still warm, I poured the manganese out upon a piece 

 of paper, when it immediately grew red hot, and set the 

 paper on fire. 



(c) The same experiment was repeated with 1 drm. ; and 

 an empty bladder was tied to the neck of the retort ; the 

 distillation was continued with a strong fire as long as the 

 bladder was distended by the air. 



This air occupied the space of 3 oz. of water. The 

 residuum in the retort afterwards weighed 35 grs., was of 

 a light grey colour, dissolved in acids, without the addition 

 of phlogiston, with a great heat. At that degree of heat 

 at which sulphur smokes, but does not take fire, it grew 

 black and began to turn red hot. From these experiments, 

 it follows that, in close vessels, phlogiston does not separate 

 from manganese, if the access of air be prevented (Sec. 

 xiv. (3)). 



SECTION XXXV. 



In Sec. xv. I observed that manganese decompounds 

 nitre, and that the acid passes over. This does not happen 



