On Sal Nitrum and Nitro-Aerial Spirit 



CHAPTER 11 



OF THE AERIAL AND IGNEOUS PART OF THE 

 SPIRIT OF NITRE 



It is shown that the Spirit of Nitre is a compound body^ and that it is 

 derived partly from the air and partly from terrestrial matter. 

 First, of its aerial part. 



In the previous chapter we treated generally of the 

 elements of which nitre is composed, and specially 

 of its more fixed part, the sal alkali^ to wit. Let us 

 look, in the next place, at the source of the other 

 element of the nitre — viz., its acid spirit. Regarding 

 this, I was for some time in doubt whether nitrous 

 spirit in a state of the finest subdivision did not reside 

 in the air and, fleeting to and fro and permeating all 

 things in virtue of its most penetrating nature, instantly 

 assail, whether from hate or rather from some con- 

 jugal affection, whatever fixed or volatile salt it at any 

 time encountered in its wandering path ; and whether 

 these two, closely united together, did not appear to 

 coalesce in a teriiiim qiiid^ to wit, common nitre. 

 And assuredly there are arguments of no little weight 

 which can be advanced in support of this hypothesis. 

 For any other source than the air for the acid spirit of 

 nitre is scarcely conceivable, since sal nitrtim is gener- 

 ated in earth which is in no way impregnated with 

 an acid salt. It is also to be noted that all salts what- 

 ever, fixed and volatile, as also vitriols, if calcined to 

 the complete expulsion of the acid spirits, acquire 

 when exposed for some time to the air a certain 



