Memoir on the Nature of fat Suhsfances. 35 



taste and smell peculiar to the animal. The suet vvJien purified 

 by oil of turpentine, is not so dry and fragile as that of ducks : 

 it melts at 3(J- R. 



Olive Oil. 

 The oil extracted from olives is no longer, as has been sup- 

 posed, an immediate simple principle : it is composed, like all 

 the fat bodies, of two distinct substances. Olive oil of good 

 quality was exposed for two days to the temperature of — 5" R.: 

 it formed into a mass of the consistence of honey : when pressed 

 at the same degree of cold in gray pajjer, a suet was obtained 

 of a brilliant white, inodorous, not very sapid, and as firm as 

 beef suet, but of far greater fusibility, for it melted at 16° R. 

 The alkalies by acting on this suet metamorphose it into oil so- 

 luble in alcohol and into an adipocire which melts at 50° R. 

 only. The oil of olives thus isolated from its suet, and pene- 

 trating the paper in which it had been pressed, was separated 

 from the paper by humecting it with warm water, and pressing 

 it again. This oil has the smell and taste of olive oil ; but when 

 exposed to a temperature of 10^ R. it does not freeze; although 

 exposed to a more considerable cold, a small quantity of suet 

 still leaves it. The property which this oil has of not freezing 

 and not becoming rancid, renders it valuable in the arts, and par- 

 ticularly to watch-makers; but it has nevertheless a great incon- 

 venience when employed in its common state; namely, as it 

 freezes at a middling degree of cold, there must be a consequent 

 irregularity in the movements of the delicate machinery to which 

 it is applied. The oil of olives, however, when deprived of its 

 suet is absolutely free from this complaint, and has all the qua^ 

 lities which we can wish. 100 parts of ohve oil at the tempera- 

 ture of — 5° R., produced: 



Oil of a greenish yellow 72 



Very white suet 28 



100 

 Without reckoning the frequent falsifications to which olive 

 oil is subject in its purest state, it is not always identical in the 

 proportion of its principles : thus the virgin oil, or that which 

 is obtained by a slight pressure of the olives, contains much less 

 suet than tliat which comes afterwards : it is therefore impro- 

 per for the manufacture of soap, and we shall presently see that 

 the suet or adipocire is indispensable in the niajiufacture of soap 

 of ifood quality. 



Oil of sweet Almonds. 



One hundred parts of oil of sweet almonds, froren at 8' or 9" 

 C 2 I^elow 



