xin THE DECOMPOSITION OF THE ALKALIS 259 



The ammonia was, therefore, a " phlogisticated " or 

 combustible substance. 



Scheele also collected the non-inflammable constituent of 

 ammonia, and showed that it was an inert gas resembling 

 " phlogisticated air " or azote. 



" If finely powdered manganese be exposed with pure 

 [nitric] acid, and some volatile alkali, to digestion 

 for several weeks, you will observe a great number of air 

 bubbles rise to the surface. This kind of air, collected in a 

 bladder tied to the neck of the flask, is not aerial acid [i.e. 

 carbonic anhydride], but of a quite different nature. 

 During the digestion, the volatile alkali is entirely decom 

 posed ; for if the solution be mixed and distilled with a 

 sufficient quantity of quicklime, not the least smell of 

 volatile alkali appears in the receiver. In this process, the 

 phlogiston, one of the constituent parts of volatile alkali, 

 has combined with the manganese, and thus rendered the 

 acid of nitre capable of acting upon the manganese. The 

 elastic fluid, collected in the bladder, has been either 

 separated from the volatile alkali, and is then its other 

 constituent part, or it is a product arising from its decom- 

 position. That the nitrous acid has no share here is 

 clearly proved by the following process : 



" I repeated the very same distillation with manganese and 

 sal-ammoniac. ... It happened here as I expected; I 

 obtained the same kind of air in the bladder as in the 

 preceding experiment " (Scheele's Essays, p. 83). 



Scheele (1777) oxidises ammonia by the calx of gold. 



Scheele prepared the same inert gas by detonating 

 FULMINATING GOLD. This substance is a compound of the 

 volatile alkali with calx of gold, prepared by adding the 

 volatile alkali to a solution of gold in aqua regia. It had 

 been known from the time of Basil Valentine to possess the 

 property of detonating violently when heated. Bergman 

 determined its composition by precipitating the calx of gold 

 by means of a fixed alkali, and then converting it into " aurum 

 fulminans " by the action of ammonia, or of one of its salts 



s 2 



