' OLEUM OLIViE. 



419 



subjected to moderate pressure in a screw press. The oil thus obtained 

 is conducted into tubs or cisterns containing water, from the surface of 

 which it is skimmed with ladles. This is called Virgin Oil. After it 

 has ceased to flow, the contents of the bags are shovelled out, mixed 

 with boiling water, and submitted to stronger pressure than before, by 

 which a second quality of oil is got. If the fruit is left for a consider- 

 able time in heaps it undergoes decomposition, yielding by pressure a 

 very inferior quality of oil called in French Huile fermeniee. The 

 worst oil of all, obtained from the residues, has the name of Jludc 



touniante or Huile d'enfer. 



It is said that in some districts the millstones are so mounted as to 

 crush the pulp without l^reaking the olive-stones, and that thus the oil 



f 



We liave 



made many inquiries in Italy and France as to this method of oil-makmg, 

 but cannot find that it is anywhere followed. 



The fixed oil of the kernels of ripe olives has been extracted and 

 examined by one of us (F.) Though the kernels have a bittensli taste, 

 the oil they yield is quite bland ; by exposure to the vapour ot hypo- 

 nitric acid, it concretes like that of the pulp. If the whole ot it were 

 extracted in making olive oil, it would only be about as 1 part ot oil ot 

 the kernel, to 40 parts of oil of the pulp. 



Description— Olive Oil is a pale yellow or greenish yellow, some- 

 what viscid liquid, of a faint agreeable smell and of a bland o/eagmous 

 taste, leaving in the throat a slight sense of acridity, its specitic 

 gravity on an average is 0-91G at iT'o C. In cold weather olive oil 

 loses its transparency by the separation of a crystaUme tatty uouy. 

 The deposition takes place at a few degrees above the freezing point ot 

 water, Ind in some oils even at 10° C. (50° F.) If the oil is a Ioaa ed to 

 congeal perfectly, and is then submitted to strong pressure about one^ 

 third of its weight of solid fat may be separated. Aiter I'epcatecr 

 crystallizations, this fat melts at 20 to 28° C. The fluid part oi Olem 

 continues fluid at - 4° to ^ 10° 0. Olive oil belongs to the class ot tne 



less alterable, non-ch-ying oils. , . ^ • i-. r.f r^^^ 



_ ^ The foregoing description does not apply to the mfer.or so,t. rf o.l. 



inferior 



have their special applications in tlie arts. 



Chemical 



om 



-The chief constituent of olive oil is Ok in 



ascertained with the fluid part of all oils of the non-drying ^la-ss^ ^'J^ 

 proportion of olein in olive oil, as well as m other ^j^^;; ^^ f 'f ^^ ^. 

 variation, the result partly of natural circumstances and partly 

 processes of manufacture. The best oils are jich m^olcm- ^^ ..,,f ;t,,tcd 

 As to the solid nnrt nf nlivo oil. Chevreui 



of Mai 



fjann 



1820. But Heintz (18 



later) showed marffai 



of glycerin and fatty acids. Collett in 



he lirst exammeu m ^^^^- ~ , nfLnrrmnuounds 

 •in to be a mixture of palmi m ^nth otl^^^l P'^^^^^ 

 zn.i.l. nollett in 1854 isolated FaiimUc Jicia, 



The Grocer, April 25, 1868, supplcuioiit ; 

 i^ereira, Ekm. of Mat Med. ii. (1850) ;505. 



and therefore in the freshest coud.t on 

 but the acrid after-taste is more perceptible 

 in oil which has hcen long kept. 



case 



•ims from the pulp 



