An ah f is of the Air. 179 



as I found by dropping a few drops of Spirit 

 of Nitre, oil of Vitriol? water, and fpittle 

 on an Anvil 1 and then holding over thofe 

 drops a piece of Iron which had a white heat 

 given it 3 upon ftriking down the hot Iron 

 with a large Hammer, there was a very great 

 explofion made by each of thofe liquors : 

 But frothy fpittle, which had air in it, made a 

 louder explofion than water 5 which fhews 

 that the vaft explofion of the Nitre and Sal 

 Tartar, which are compofed of elaftick air 

 particles, included in an acid Spirit 7 is owing 

 to their united force. 



We may therefore from what has been 

 faid, with good reafon conclude, that Fire is 

 chiefly invigorated by the aftion and re= ac- 

 tion of the acid fulphureous particles of the 

 fuel, and the elaftick ones which arife and en- 

 ter the Fire, either from the fuel in which 

 they abound, or from the circumambient 

 air: For by Experiment 103, and many 

 others, acid fulphureous particles ad vi- 

 goroufly on air $ and fincea&ion and re-a&ion 

 are reciprocal, fo muft air onfulphurj and 

 there is, we fee, plenty of both 5 as well in 

 mineral as vegetable fuel, as alfo in animal 

 fubftances, for which reafon they will burn. 

 T 4 But 



