Oji Sal Nitrum and Nitro- Aerial Spirit 15 



great hindrance to fire, since it is exceedingly well 

 adapted for extinguishing fiery particles. But although 

 the spirit of nitre will not deflagrate if put into a 

 flame, yet if it is poured upon salt of tartar, nitre will 

 be generated from the combination, and if this be 

 thrown into the fire it will immediately produce flame. 

 But we must suppose that the flame of this deflagrat- 

 ing nitre is caused by the igneo-aerial particles of the 

 nitrous spirit being thrown into agitation. For the 

 salt of tartar of which the rest of the nitre is com- 

 posed seems to be very alien to the nature of flame, 

 as we have shown above. But the reason why the 

 igneo-aerial particles of nitrous spirit are well adapted, 

 when combined with fixed salt, for producing flame, 

 seems to be this, that when the spirit of nitre unites 

 with fixed salt to form nitre, its humidity being lost, 

 it changes into a dry and rigid substance ; so that as 

 its igneo-aerial particles exist now in a dry condition, 

 there is no obstacle to their commencing a fiery 

 motion. 



Further, nitro-aerial particles must, it appears, if 

 they are to take the form of flame, enter into close 

 combination with a fixed salt, or with something else 

 to take the place of the fixed salt ; so that they may 

 be torn violently and with elastic force from their 

 partner and thrown into a state of the most rapid 

 motion, as I shall endeavour to show below. 



