On Sal Nitrunt and Nitro-Aerial Spirit 167 



we note further that oil of vitriol, when put into it, 

 does not produce in it effervescence, or precipitation, 

 or any degree of heat. And yet it is certain that the 

 acid salt of vitriol unites with the fixed salt of the 

 lime. For if spirit of vitriol be poured into a solution 

 of sulphur made in water that has slaked quicklime, the 

 sulphur will be immediately precipitated, as we have 

 already remarked. And yet this would certainly not 

 happen unless the acid of the vitriol uniting with the 

 fixed salt of the lime drove the sulphur from its 

 lodgment. 



But to make the reason of this clear, it should be 

 noted that if salts which are somewhat saturated and 

 weakened by their opposites, afterwards meet a salt 

 that is still more repugnant, there will yet be no 

 effervescence or heat from their mutual action as there 

 would be in other circumstances. For example, if oil 

 of vitriol be united with any metal whatever with a 

 distinct ebullition (as is the case when iron is 

 dissolved in oil of vitriol) and then fixed salt of tartar 

 is put into that solution, although the acid spirit of 

 the vitriol combines with the salt of tartar, and the 

 metal now liberated from the acid salt is precipitated, 

 still no ebullition or heat will be produced in so far as 

 the acid spirit of the vitriol was previously to some 

 extent saturated by the metal joined to it. And the 

 same thing also happens when salt of tartar is mixed 

 with a solution of sal armoniac. For when this is 

 done the salt of tartar absorbs, without any ebullition, 

 whatever acid there is in the sal armoniac. 



And for a perfectly similar reason the alkaline salt 

 of the water in which quicklime has been slaked unites 

 without any effervescence with oil of vitriol poured 

 into it, because the alkaline salt of the lime has been 

 previously saturated with its own acid. Consequently 



