158 Mayow 



calcination of the calcareous stone. For as the acid 

 spirit of sulphur is produced from the more fixed par- 

 ticles of common sulphur, also the spirits of vitriol and 

 of nitre from metallic or earthy sulphur, by the action 

 of nitro-aerial and igneous spirit, as I have before 

 attempted to show, so it is likely that the nitro-aerial 

 particles of fire encounter, in the course of the long- 

 continued calcination of the calcareous stone, the more 

 fixed particles of the sulphur of the stone (for cal- 

 careous stone, like flints, contains much sulphur), and 

 rub and sharpen them, and at last convert them into 

 an acid salt in the manner described above. 



Let us see next how it is that contrary salts — acid, 

 to wit, and alkali — subsist together in quicklime and 

 yet do not act upon each other until water is poured 

 on the lime. As regards this, it is probable that the 

 acid spirit of quicklime becomes so sharp and fiery in 

 consequence of its long calcination, as to be altogether 

 unfit for engaging with fixed salts until its more 

 powerful igneous force is diluted by admixture with 

 water and to some extent moderated ; for saline 

 solvents are sometimes so corrosive that they fail to 

 dissolve or in any way affect metals, which in their 

 nature closely resemble fixed salts, till their too keen 

 force is diminished by admixture of water. 



Further, the fixed, like the acid, salt of the quick- 

 lime becomes in the highest degree biting and fiery 

 by reason of the fiery particles infixed in it during 

 its long calcination. For it is to be noted that 

 although nitro-aerial and igneous particles are of a 

 saline nature, still they are opposed neither to acid salt 

 nor to alkali, but, on the contrary, when combined 

 with either, increase its power and render it fiery. But 

 since nitro-aerial particles are fixed in dense number 

 in the acid, and in the fixed, salt of lime, it comes to 



