122 Mayow 



and there impinging upon the subtle matter agitated 

 with extreme velocity, are, by its impulse, thrust out 

 with elastic violence along with the nitro-aerial par- 

 ticles which these substances contain ; so the milder 

 fermentation of natural things must be supposed to 

 arise from this, that nitro-aerial particles, along with ex- 

 traneous moisture, penetrate a saline-sulphureous mass 

 and enter the abode of the subtle matter, by which, as 

 it is in violent agitation, the nitro-aerial together with 

 the sulphureous particles are driven off. For fiery 

 effervescence seems to differ only in this respect 

 from the milder internal motions by which plants 

 hasten to growth or decay, that in fire, nitro-aerial 

 particles, in close union wdth fixed salt or with aerial 

 particles, are, by the impulse of sulphureous particles 

 and of the subtle matter, violently sundered from their 

 partner and thrown into very brisk motion ; whereas, 

 on the other hand, in the said fermentations, as the 

 sulphureous particles are not held so firmly in the 

 •embrace of fixed salt, they are thrown into a milder 

 motion by the impact of the nitro-aerial particles and 

 of the subtle matter. But these matters have been 

 more fully discussed elsewhere. Nor does the process 

 seem to be different in the effervescence of opposed 

 liquids, for when one of these intrudes into the pores 

 of another, and therefore also into the abode of the 

 subtle matter, and is expelled again, an internal move- 

 ment and effervescence of the particles is set up. 



WHY THE FORM OF FLAME IS ALWAYS 

 POINTED 



As to fire, let us consider lastly why flame of every 

 -sort rises to a point. On this it is to be remarked, 

 in the first place, that the sulphureous particles, burst- 

 ing out from the burning matter, pass through the 



