On Sal Nitrum and Nitro- Aerial Spirit 51 



were. But in fact what should force the aqueous 

 particles set in motion by the subtle matter into other 

 situations, once they have adapted their forms to the 

 dimensions of the places in which they are ? For 

 they should rather retain the same situation by ceasing 

 to move. For particles adapted to any space would by 

 no means change their position and recede from each 

 other with conspicuous force (as happens with frozen 

 water, which breaks through the strongest glass), unless 

 some force were applied to those particles. 



It is probable then that nitro-aerial particles enter 

 the pores of the water pointwise and like wedges draw 

 them somewhat apart from one another so that the 

 mass of that water has to dilate and swell, the aqueous 

 particles meanwhile passing from a flexible to a rigid 

 condition owing to the nitro-aerial particles which are 

 fixed in them, so that they no longer flow hither and 

 thither but are joined and, by cohering firmly together, 

 constitute a solid body. 



We note here in passing that as nitro-aerial particles 

 arrest the movement of aqueous particles and freeze 

 them, so nitro-aerial particles when secured in their 

 turn among aqueous particles are as it were fettered 

 and fixed. And this seems to be the reason why 

 water is specially adapted for extinguishing flame ; 

 while yet, on the other hand, sulphureous and nitro- 

 aerial particles mutually agitate and repel each other. 

 And hence it is that spirituous liquids which contain 

 volatile sulphur are never frozen. For if wine be 

 exposed to the cold of winter all the spirituous and 

 sulphureous particles of the wine will be driven into 

 the mid-liquid and only the aqueous particles circu- 

 lating round them will be frozen. Indeed the nitro- 

 aerial particles ward off and repel as much as possible 

 the sulphureous particles and surround them, when 



