On Sal NitriLm and Nitro- Aerial Spirit 159 



pass that these contrary salts are kept apart and, as it 

 were, reconciled by the mediation of the nitro-aerial 

 particles which are in harmony with both, so that 

 they are unable mutually to attack or act upon each 

 other. But when these salts are diluted with water, 

 they lay aside, at least to some extent, their fiery 

 particles and become less acrid, as will be apparent 

 if fixed salts exposed to a hot fire are afterwards dis- 

 solved in water ; for then the salts which the fire has 

 made extremely acrid and caustic will lay aside their 

 acridity and return to their original state. Hence 

 it is that the contrary salts of lime, after they have 

 been dissolved in water, are then fit for acting upon 

 each other and for mutual effervescence. 



And in this we have an explanation of the fact that 

 quicklime does not become hot when sprinkled with 

 spirit of wine or other sulphureous liquids of that sort, 

 as has been said before. For since such liquids are 

 incapable of dissolving the fixed salt of the lime, they 

 cannot temper its too acrid and fiery force ; yet this 

 is absolutely necessary for producing its heat. 



I add, lastly, that the acid salt of the lime seems to 

 contract a somewhat dry nature on account of the 

 very dry and solid nitro-aerial particles densely fixed 

 in it ; whence it is that that acid spirit can remain so 

 long in the hottest fire. For the extremely solid 

 nitro-aerial particles, densely fixed in the acid salt, 

 make it somewhat rigid, so that its particles cannot 

 be carried aloft by any force of fire. And hence it 

 is that that acid salt of lime, being of a drier nature, 

 will not engage with its fixed salt until it has been 

 dissolved by pouring water upon it. 



But yet another difficulty is here presented. For 

 admitting that contrary salts exist in Hme and in the 

 water in which it has been slaked, how does it 



