[ iM ] 
cold, nobody will be furprifed, that a Stream of 
the Matter of Fire may produce Cold. 
If all the alcalious Corpufcles burfted at once, the 
Fermentation would laft but an Inftant : But as the 
acid Liquor requires a certain Space of Time, to pe- 
netrate the whole alcaline Liquor, and fill the Pores 
of the alcalious Corpufcles, the Fermentation is per- 
formed fucceflively in a certain Number of Cor- 
pufcles at a time, until they are all broken: And 
this Succelfion conflitutes the Duration of the Fer- 
mentation ; which ceafcs when there are none of 
the Alkali’s left entire. 
Thcfe Principles not only ferve to explain the 
Fermentation which refults from the Mixture of 
Acids and Alkali’s, but alfo almoft all the Motions 
of this Kind, which are occafioned by the Mixture 
or Penetration of two or more Subftances. 
For Example ; Lime, which we have mentioned 
above as a Body filled with the Matter of Fire, and 
which produces an Effervcfcence capable of lighting 
Sulphur, if Water be thrown on it; Lime, 1 fay, 
produces this Effeft, only becaufe the Particles of 
Water, which enter into its Pores, have a Ten- 
dency to fhut up the igneous Particles more elofely. 
It is by a Mcchanifm entirely fimilar, that Hombergs 
Phofphorus kindles into Flame, upon being expolld 
to the Air: ’Tis upon this Principle likewife, that a 
Mixture of Spirit of Wine and Water acquires a 
new Degree of Heat; and fo of other Phenomena 
of this Nature. 
• Le Cat. 
XVII. 
