26 Mayow 



and almost harmless. For if a finger or anything 

 combustible is thrust into the blue flame of sulphur, 

 but not into the sulphur mass, it will not be burned 

 as by other fires, but will remain for some time 

 uninjured. To this we add further that the flame 

 of sulphur does not expand like other flames but 

 bursts forth from time to time and seems as it were 

 to eff'ervesce. From this it is to be inferred that 

 there is a third substance mixed with it on which the 

 fiery particles act. And that these particles, of a saline 

 or metallic nature, mixed with the flame of the sulphur 

 and sharpened by the rubbing of the nitro-aerial 

 particles and brought at last to a fluid state, constitute 

 the acid and corrosive spirit of sulphur, we take to be 

 at least a probable conjecture; for otherwise I have no 

 notion how the acid spirit is produced, for it is improb- 

 able that it exists in the structure of the sulphur 

 before its combustion, as has been shown above. 



To this we further add that the oil of vitriol expelled 

 after several days' distillation seems to be produced 

 in nearly the same way. For it is certain from 

 experience that if the distillation of vitriol is con- 

 tinued with the strongest fire for ten or even more 

 days, acid spirit will still all the while pass into the 

 receiver. But it is scarcely to be believed that any 

 acid spirit is so fixed and ponderous as to be able to 

 remain so long in the hottest fire. We must rather 

 suppose that nitro-aerial particles of the fire, in the 

 course of the long continued distillation of the vitriol, 

 encounter the metallic sulphur of the colcothar and 

 effervesce — the result being that the saline particles 

 of that sulphur which are placed among the mutually 

 rubbing fiery particles are pounded and comminuted 

 so as at last to be sharpened and brought into a fluid 

 state. And these at last carried up by the force of 



