caft upon it. And then to the Specifick Gravity the 
difference is aifo very confiderable, which any one may 
find by this famiUar u/ay : If you fill a Glafs with one 
Ounce of the Eflential Oyl of the Seeds, you will re- 
quire Nine Dranns of the Ponderous Oyl of the Vege- 
table to fill up the fame fpace. 
This is alfo very obvious to any Speftator, that mofl: 
of thefe Oyls thus diftilled are more Ponderous than 
common Water, by their finking to the bottom ; where- 
as all our Eflential Oyls drawn from the fiedy parts, do 
fwim on Water, and (bme are lighter than the beft re- 
ctified Spirit of Wine, but mod are lighter than Brandy, 
which has made our Chymifts call them iEtherial 
Oyls. 
In the Catalogue of Experiments you may find which 
are the Ponderous Oyls, that do conftantly take fire. 
Moreqver the Ponderous Oyls have yet one Advantage 
above the lighter Volatile Oyls, they having been ex- 
pofed to a longer and ftronger degree of Fire than the 
others, and fo do incorporate more Igneous Particles 
with it felf, which being put into motion, may contri« 
bute fomething to caufc this Acccnfion. 
The Oyls diftilled from Animal Bodies do all of them ' 
take Fire and Flame, but with this difference, they do 
not make fo great an Explofion as the Vegetable do , 
but do more certainly take fire, and will continue their 
flame longer, but not Co fierce as the other. If we 
rightly Examine the Conftitution or Texture of this 
Oyl, we have feveral Properties adapted to the Produ- 
dlion of this EfTefl:. You have a much greater degree 
of Fire required in the Diftillation of this Oyl than is 
ncceflary for that of the Vegetable. You have alfo a 
great quantity of Volatile Salts ( which are true Al- 
kalies) that do pafs over with your Oyl; And you 
have a Ponderous Oyl, that finks in Water; which be- 
ing confidered and weighed rogether, do make it equi-l i 
table 
