32 Mayow 



against the nitro-aerial particles and set them in 

 igneous motion. 



I add further in confirmation of what has been said, 

 that the nitro-aerial particles to which the elastic force 

 of the air is due are fixed in the aerial particles them- 

 selves and are torn from them by the burning of a 

 lamp or by the breathing of animals ; for that the 

 nitro-aerial and elastic particles which are lacking in 

 the afore-mentioned glass vessels are neither air itself 

 nor some material interspersed among its particles, has 

 been shown above, and therefore it must be concluded 

 that the elastic particles are implanted in the particles of 

 the air themselves and constitute their more active part, 

 and that it is in fine because these are driven out from 

 the aerial particles by the burning of fire or by the 

 breathing of animals that air becomes quite effete and 

 destitute of elastic force. 



That the igneo-aerial particles are not air itself pure 

 and simple, but only its more subtle part, may be 

 inferred besides from this, that nitro-aerial particles, 

 whatever they be, exist in nitre and constitute its fiery 

 and aerial part, as was shown above. But who can 

 imagine that air itself resides in such abundance in 

 nitre as is required for its burning in a place void of 

 air ? If spirit of nitre be poured upon any fixed salt 

 when taken fresh from the fire, nitre will be produced 

 by their union ; but it is not to be supposed that air is 

 present in such quantity in either of these principles, 

 nor can we believe that air coalesces along with 

 these principles in the generation of nitre. Nor is it 

 probable that air without any force applied to it would 

 condense to such an extent as would have to be 

 supposed in the case of nitre if its burning resulted 

 from air residing in it. For to the production of so 

 impetuous a flame as is produced by a small morsel of 



