154 Mayow 



particles are fixed in it and are firmly detained in its 

 structure which is even harder after calcination than 

 before, and that afterwards these particles, driven 

 out of their quarters by the water poured on the lime^ 

 burst forth and by their motion produce heat. But 

 indeed it seems to me scarcely probable that igneous 

 particles are fixed in quicklime in this way, for its 

 structure seems to be too loose to detain the extremely 

 agile nitro-aerial particles. But even supposing igneous 

 particles to exist in quicklime, how should the pouring 

 of water upon it rouse them to the motion requisite 

 for heat ? For aqueous particles are of a nature to 

 arrest the motion of igneous particles and to extinguish 

 them, but not to throw them into motion. 



Wherefore we are ^t liberty to suppose that nitro- 

 aerial and igneous particles exist in quicklime, not 

 simply and by themselves, but closely combined 

 with some salt, and that the heat which arises when 

 water is sprinkled upon it is due to the existence in 

 it of contrary salts — an acid, to wit, and an alkali — 

 and to their action upon each other. 



For, first, we must hold that a fixed salt is contained 

 in quicklime. For if quicklime is thrown upon an 

 acid liquid, such as water with which oil of vitriol has 

 been mixed, the water will presently be deprived of all 

 its acidity, since the fixed salt of the lime immediately 

 absorbs and destroys the acid salt of the vitriol, being 

 contrary to it. 



Further, if spirit of vitriol be poured upon quick- 

 lime slaked by pouring water on it and not yet quite 

 dry, heat and a pretty brisk fermentation will result 

 from their action upon each other — a clear proof that 

 an alkaline salt exists in quicklime. For in this case 

 the heat in the previously slaked lime does not arise 

 from the moisture of the vitriolic spirit but from the 



