OIL. 
volatile oils, but are not fo volatile as to admit of diftillation: 
The vegetable containing the oil is infufed in alcohol, which 
eee the oil. The alcohol is nea diftilled from 
the 
Thele oils are faid to be say ina which appears to be 
their moft diftinguifhing chara An oil of this kind is 
obtained from the root o the feliebords bvemalie, and an- 
other is - nd in to pac 
pproach the nature of vola- 
ation of vegetable 
Ons, Empyreuma ~Thefe a 
tile als; and are formed coke 3 the difti 
and animal fubftances. They have properties nearly allied to 
tar, and afford, by a fecond er care = l he Lae tion, gusta 
volatile oil, not much unlike the n tar. 
has many properties in common with ‘ol “of pa ntin 
fimilar fubftance is obtained from pit-coal by diftillaticn, 
which oil belongs alfo to this clafs. 
The colour of et ate vegetable oil is yellowifh- 
n 
than before, though ftill 
ele of much of its enpyeunte flavour. See Aikin’s 
5 
Cc 
3 
~O 
< 
a 
o; 
Th e = of oil in fopping the viclent ebullition of various 
ife 
< 
09 
“ 
oO 
Ss 
ct 
ote 
f=] 
3 
p 
f=) 
a 
9° 
Qa 
ie) 
BS) 
us 
fo} 
t=] 
an 
fo) 
wate 
gar r the like, 
be be boiling on re, and in danger of nine over ihe fides 
of the veffel, athe pouring in a little oil immediately makes 
it fubfide. many cafes, the marking a circle round the 
to the oil, at, con 
important ufe afc e occafion, which i 
pouring a little of it on any metallic folution, while making ; 
this reftrains the afcent of the noxious cet ag Geis 
thé operator from danger ; and, at the fam 
ing down - hie g matter, pee redoubled Cae a 
the men 
iny ings s Cmiengoned a pal aia a effe& of oil, in 
Rilling the furface of w n it is agitated with 
waves, and the ufe made a it by the divers, for this eee 
pofe. ‘ Omne,”’ fays he, ‘‘ oleo a ba &c. lib. i 
cap. 103. and Plutarch, in Quett. afks, ** Cur r mare 
oleo confperfum ee um fit et ai uillum ??? Pliny’s 
accoun feems to have been either diferedited or es 
iters on experimental amr oie till it was con 
finned by feveral r. Franklin, which 
were publifhed in the year 1744. 
The property of oil above-mentioned has, however, been 
s for oyfters, at 
di 
cnrione 
which they now and then let out ; 
on rifing to the furface of the fea, immediately renders it 
{mooth, fo as to permit the light to pafs through the water, 
undifturbed by various and irregular refraGtions. 
Bermudians, it is ~ are ener to fee on bole 
ould be concealed fro eir view, through 
a, “ coirie a a ite oil ra it. 
Lifbon fifhermen effec a fafe paflage over the bar 
of Tagus, by emptying a bottle or two of oil into the 
fea, at the furf is fo great as to endanger its filling their 
boats. Our failors have alfo abled: that the water is al- 
ways much fmoother in the wake 2 a ns that hath been 
newly pea = it is in one t' ati 
Dr. Franklin by an aeoieitl obfery vation made 
at fea in 1757, to attend paeicokaly to Pliny’s account ; 
and ne various t cton s which he afterwards received 
relating to it, induced cay to try fome experiments on the 
fubjet. Standing on the windward fide of a large pond, 
the furface of which was rendered very rough with the wind, 
he poured a tea-fpoonful of oil on ee — oF {mall 
quantity inary an inftant calm feveral 
pread amazin 
-glafs 
fuc ed, one circumftance 
prize; this was the fudden, wile, ie forcible fpreading of 
nek of oil on the face of the water, which, he adds, ‘I 
do not ane - any body has ore 
he oil is put on a looking ane or polifhed 
marble, it fpreads a little: but on w ve tly *eX- 
pands into 1 » b 
meee ever 
from a centre, leaving a large clear fpace. ‘The quantity 
of this force, and the diftance to which i it will operate, the au- 
ous pa at n 
endeavouring t t for the Bngula effeéts of oi], Dr. 
ee cbierve, that die feem no natu ural repulfion 
b fo as to | ies from coming into 
contaét with each other. Therefore air, in motion, which 
contin e the elem ut 
aves. e {malleft wave does ai ne fublide, at 
te ae nearly as much of the water next to it. 
A {mall power, continually ete will produce a great 
aGtion: fo that the firlt raifed waves, being continually aéted 
upon by the wind, are, though the wind does not increafe 
in ftrength, continually increa{fed in magnitude, rifing higher 
and extending their ba es, fo as to include a vaft mafs of 
water in each wave, which, in its motion, acts with great 
iolence. But if there be, a mutual repulfion between the 
pees of oil, and no attraCtion between oil and water, oil 
dropt on water will not be held together by adhefion to the 
{pot on which it falls; it will not be imbibed by the water ; 
