Ii8 Mayow 



the second occasion would have survived twice as long 

 as the previous one. And the reason that the animal, 

 when the said air was put into the glass with it, lived 

 a little longer than it would otherwise have done, 

 appears to be that the air enclosed in the glass could 

 be more gradually and less copiously breathed and cor- 

 rupted by the animal in consequence of the admixed 

 air. 



Here, too, we might repeat our remarks in the 

 previous chapter on the difference between this sort 

 of air and common air. And yet it is probable that 

 there is a great likeness between air of this kind and 

 common air, and that the elastic force of both is due 

 to no very diff*erent cause. For since iron consists of 

 rigid particles, and the corrosive spirits consist of very 

 elastic nitro-aerial particles, as has been elsewhere said, 

 the air produced by their fermenting together will not 

 be very different from common air, inasmuch as the 

 latter appears to be formed of rigid particles, and these 

 imbued with nitro-aerial spirit, as I have elsewhere 

 endeavoured to show. 



CHAPTER X 



HO W FIRE IS PRO PA GA TED. ALSO WHY FLAME 

 RISES TO A POINT 



In the preceding chapters the nature of fire has been 

 frequently discussed ; let us now inquire how it is that 

 fire, so very small when first kindled, spreads itself 

 so enormously if only it be supplied with sufficient 

 abundance of sulphureous nutriment. For it is to be 

 noted that nitro-aerial and sulphureous particles, when 



