668 rHII-OSOPHICA.L TRANSACTIONS. [anNO I694. 



more igneous particles, which being put in motion, may contribute something 

 to cause this accension. 



The oils distilled from animal bodies do all take fire and flame, but with this 

 difference, that they do not produce so great an explosion as the vegetable do, 

 but they more certainly take fire, •nd will continue their flame longer, though 

 not so fierce as the other. If we rightly examine the constitution or texture 

 of this oil, we have several properties adapted to the production of this effect. 

 There is a much greater degree of fire required in the distillation of this oil 

 than is necessary for that of the vegetable ; also a great quantity of volatile salts 

 pass over with the oil ; and you have a ponderous oil that sinks in water ; all 

 which being considered and weighed together, make it probable that a more 

 constant accension will en«ue from the animal oils than from any other. 



Oleum succini is justly put in the catalogue of minerals, and is produced by 

 a strong degree of fire ; yet it causes no motion, and scarcely any incalescence, 

 notwithstanding it abounds in volatile salts ; the reason is, because these salts 

 are not properly volatile, as alkalies are, but belong to the family of acids, and 

 so can make no fermentation with this compound spirit, which is itself highly 

 acid. 



I shall venture here to add one surprising effect of this fiery mixture, as 

 follows : 



We took half a dram of the oil of carui-seeds, and poured it into a little 

 gallipot, and put a dram of our compound spirit of nitre in a small phial into 

 the same gallipot, and placed over it a glass that held 3 pints on M. Papin's 

 exhausting engine : and having cleared it of the air, we turned up the phial in 

 order to see what effect would ensue, in this sort of vacuum, on this mixture ; 

 but in a moment the receiver was blown up, and the mixture in a flame ; which 

 is the more surprising as Mr. Boyle found that in all his experiments the 

 removal of the air did almost always extinguish light, fire, and flame. The 

 blowing up of the glass also makes the experiment the more extraodinary, and 

 puzzles one how to account for so great a quantity of air as was produced from 

 these liquors, which amounted only to a dram and a half; for here was required 

 not only air enough to fill up the capacity of the vessel, but also so great a 

 pressure within as exceeded that great incumbent weight of the air that pressed 

 upon this capacious glass without, whose diameter was 6 inches and the depth 

 above 8, for otherwise it would not have thrown it up into the air. i 



This fiery mixture and gunpowder agree, in that they both heat, burn, and 

 flame ; and also considerably resist and raise up bodies that oppose them ; in 

 both the air is much agitated and expanded. 



