On Sal JVitrum and Nitro- Aerial Spirit 25 



shown above. But as the minutely divided saHne 

 particles of the sulphur are very closely united to its 

 sulphureous particles, it happens in the deflagration 

 of sulphur (when the sulphureous and nitro-aerial 

 particles throw each other into fiery motion) that the 

 saline particles of the sulphur, adhering to its sul- 

 phureous particles, are by frequent impacts of the 

 nitro-aerial particles struck, rubbed, and comminuted, 

 so that the saline particles from being often rubbed 

 and pounded, are at last sharpened like small swords 

 and are moreover so attenuated as to be changed from 

 rigid and solid into flexible and fluid particles. The 

 saline particles of the sulphur in fact which were 

 previously of a fixed nature change, after they are 

 thus sharpened and made fluid, into an acrid and acid 

 liquid, and probably constitute the common spirit of 

 sulphur. 



That the facts of the case are as stated may be 

 inferred from a careful study of the flame of sulphur 

 since it is very different from other flames. For 

 nitro-aerial particles do not shine ruddily and glow 

 in the flame of burning sulphur as in other cases, but 

 owing to their diminished motion appear blue, so that 

 it would appear that some third substance is interposed 

 between the nitro-aerial and sulphureous particles, 

 and that by it these fiery particles are hindered in 

 their motion. For as the nitro-aerial and fiery 

 particles, when in violent agitation, glow, so when 

 their motion is retarded they appear of a blue colour. 

 And this is the reason that the flame of an expiring 

 lamp is wont to be blue. But of this more else- 

 where. 



It serves to confirm what has been said that the 

 flame of sulphur in consequence of the somewhat 

 sluggish movement of the fiery particles is less caustic 



