See also:

• OILS (adopted from the Fr. oile, mod. huile, Lat. oleum, olive oil)

OILS (adopted from the Fr. oile, mod. huile, See also:

• LAT

Lat. oleum, See also:

• OLIVE (Olea europaea)

olive oil)  , the generic expression for substances belonging to extensive See also:

• SERIES (a Latin word from serere, to join)

series of bodies of diverse chemical See also:

• CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character, all of which have the See also:

• COMMON

common See also:

• PHYSICAL

physical See also:

• PROPERTY

property of being fluid either at the See also:

• ORDINARY (med. Lat. ordinarius, Fr. ordinaire)

ordinary temperature cr at temperatures below the boiling-point of See also:

• WATER

water . Formerly, when substances were principally classified by obvious characteristics, the word included such a See also:

• BODY

body as " oil of See also:

• VITRIOL

vitriol " (sulphuric See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid), which has of course nothing in common with what is now understood under the See also:

• TERM

term See also:

• OILS (adopted from the Fr. oile, mod. huile, Lat. oleum, olive oil)

oils . In its most comprehensive ordinary acceptation the word embraces at See also:

• PRESENT

present the fluid fixed oils or fatty oils (e.g. See also:

• OLIVE (Olea europaea)

olive oil), the soft fats which may be fluid in their See also:

• COUNTRY (from the Mid. Eng. contre or contrie, and O. Fr. cuntree; Late Lat. contrata, showing the derivation from contra, opposite, over against, thus the tract of land which fronts the sight, cf. Ger. Gegend, neighbourhood)

country of origin (e.g. coco-See also:

• NUT
• NUT (0. Eng. knutu, cf. Dutch noot, Ger. Nuss; allied with Gael. cno; it is not of the same form as Lat. nux)

nut oil, See also:

• PALM (Lat. palma, Gr. iraX6.jn )
• PALM, JOHANN PHILIPP (1768-1806)

palm oil), the hard fats (e.g. See also:

• TALLOW (M.E. talugh, talg, cf. Du. talk, L. Ger. talg ; the connexion with O.E. taelg, dye, or Goth, tulgus, firm, is doubtful)

tallow), the still harder See also:

• VEGETABLE

vegetable and See also:

• ANIMAL
• ANIMAL (Lat. animalis, from anima, breath, soul)

animal waxes (e.g. carnauba See also:

• WAX

wax, beeswax), the odoriferous ethereal (essential) oils, and the fluid and solid volatile See also:

• HYDROCARBONS

hydrocarbons—See also:

• MINERAL

mineral hydrocarbons—found in nature or obtained from natural products by destructive See also:

• DISTILLATION (from the Lat. distillare, more correctly destillare, to drop or trickle down)

distillation . The common characteristic of all these substances is that they consist principally, in some cases exclusively, of See also:

• CARBON (symbol C, atomic weight 12)

carbon and See also:

• HYDROGEN [symbol H, atomic weight x-oo8 (0=16)]

hydrogen . They are all readily inflammable and are practically insoluble in water . The mineral hydrocarbons found in nature or obtained by destructive distillation do not come within . the range of this See also:

• ARTICLE (from Lat. articulus, a joint)

article (see See also:

• NAPHTHA

NAPHTHA, See also:

• PARAFFIN

PARAFFIN, See also:

• PETROLEUM (Lat. Petra, rock, and oleuin, oil)

PETROLEUM), which is restricted to the following two large See also:

• GROUPS
• GROUPS, THEORY

groups of bodies, formed naturally within the vegetable and animal organisms, viz . (I) Fixed oils, fats and waxes, and (2) Essential, ethereal or volatile oils . 1 . Fixed Oils, Fats and Waxes . The substances to be considered under this See also:

• HEAD (in 0. Eng. heafad; the word is common to Teutonic languages; cf. Dutch hoofd, Ger. Haupt, generally taken to be in origin connected with Lat. caput, Gr. KerbOvi7)
• HEAD, SIR EDMUND WALKER, BART
• HEAD, SIR FRANCIS BOND, BART

head See also:

• DIVIDE

divide themselves naturally into two large classes, viz. fatty (fixed) oils and fats on the one See also:

• HAND
• HAND (a word common to Teutonic languages; cf. Ger. Hand, Goth. handus)
• HAND, FERDINAND GOTTHELF (1786-185r)

hand, and waxes on the other, the distinction between the two classes being based on a most important chemical difference . The fixed oils and fats consist essentially of glycerides, i.e. See also:

• ESTERS

esters formed by the See also:

• UNION
• UNION (known locally as Union Hill and officially as Town of Union)

union of three molecules of fatty acids with one See also:

• MOLECULE (from mod. Lat. molecula, the diminutive of moles, a mass)

molecule of the trihydric See also:

• ALCOHOL

alcohol See also:

• GLYCERIN, GLYCERINE

glycerin (q.v.), whereas the waxes consist of esters formed by the union of one molecule of fatty acid with one molecule of a monohydric alcohol, such as cetyl alcohol, cholesterol, &c . Only in the See also:

• CASE
• CASE, JOHN (d. 1600)

case of the wax coccerin two molecules of fatty acids are combined with one molecule of a dihydric (bivalent) alcohol .

It must be pointed out that in common parlance this distinction does not find its ready expression . Thus See also:

• JAPAN

Japan wax is a glyceride and should be more correctly termed Japan tallow, whereas sperm oil is, chemically speaking, a wax . Although these two classes of substances have a number of physical properties in common, they must be considered under See also:

• SEPARATE

separate heads . The true chemical constitution of oils and fats was first expounded by the classical researches of See also:

• CHEVREUL, MICHEL EUGENE (1786-1889)

Chevreul, embodied in his See also:

• WORK

work, Recherches sur See also:

• LES

les See also:

• CORPS (pronounced as in French, from which it is taken, being a late spelling of tors, from Lat. corpus, a body; cf. " corpse ")

corps gras d'origine animale (1823, reprinted 188g) . (a) Fatty (fixed) Oils and Fats.--The fatty (fixed) oils and fats See also:

• FORM (Lat. forma)

form a well-defined and homogeneous See also:

• GROUP

group of substances, passing through all gradations of consistency, from oils which are fluid even below the freezing-point of water, up to the hardest fats which melt at about 5o° C . Therefore, no See also:

• SHARP, GRANVILLE (1735-1813)
• SHARP, JAMES (1618-1679)
• SHARP, JOHN (1645-1714)
• SHARP, RICHARD (1759-1835)
• SHARP, WILLIAM (1749-1824)
• SHARP, WILLIAM (1856-1905)

sharp distinction can be made between fatty oils and fats . Nevertheless, it is convenient to apply the term " oil " to those glycerides which are fluid below about 2o° C., and the term " See also:

• FAT (O.E. fdett; the word is common to Teutonic languages, cf. Dutch vet, Ger. Fett, &c., and may be ultimately related to Greek Irian, and =apos, and Sanskrit pivan)

fat " to those which are solid above this temperature . Chemical See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

Composition.—No oil or fat is found in nature consisting of a single chemical individual, i.e. a fat consisting of the glyceride. of one fatty acid only, such as stearin or tristearin, C3H8(O.C18H350)3, the glycerin ester of stearic acid, C17H35,See also:

• CO2H

CO2H . The natural oils and fats are mixtures of at least two or three different triglycerides, the most important of which are tristearin, tripalmitin, See also:

• C3H5(OH)2
• C3H5(OH)3+3(C10H31O2)H

C3H5(O•C,6H31O)3 and triolein, 'C3H5 (O•C1811330)3 . These three glycerides have been usually considered the See also:

• CHIEF (from Fr. chef, head, Lat. caput)

chief constituents of most oils and fats, but latterly there have been recognized as widely distributed trilinolin, the glyceride of linolic acid, and trilinolenin, the glyceride of linolenic acid . The two last-named glycerides are characteristic of the semi-drying and drying oils respectively . In addition to the fatty acids mentioned already there occur also, although in much smaller quantities, other fatty acids combined with glycerin, as natural glycerides, such as the glyceride of butyric acid in See also:

• BUTTER (Lat. butyrum, Gr. 0obrvpov, apparently connected with $ous, cow, and rvpbs, cheese, but, according to the New English Dictionary, perhaps of Scythian origin)

butter-fat, of caproic, caprylic and capric acids in butter-fat and in coco-nut oil, lauric acid in coco-nut and palm-nut oils, and myristic acid in See also:

• MACE (Fr. masse, O. Fr. mace, connected with Lat.'ntateola, a mallet)

mace butter .

These glycerides are, therefore, characteristic of the oils and fats named . In the classified See also:

• LIST (O.E. lisle, a Teutonic word, cf. Dut. lust, Ger. Leiste, adapted in Ital. lista and Fr. lisle)
• LIST, FRIEDRICH (1789-1846)

list below the most important fatty acids occurring in oils and fats are enumerated (cf . Waxes, below) . Oils and fats must, therefore, not be looked upon as definite chemical individuals, but as representatives of natural See also:

• SPECIES

species which vary, although within certain narrow limits, according to the See also:

• CLIMATE

climate and See also:

• SOIL

soil in which the See also:

• PLANTS

plants which produce them are grown, or, in the case of animal fats, according to the climate, the See also:

• RACE

race, the See also:

• AGE (Fr. age, through late Lat. aetaticum, from aetas)

age of the animal, and especially the See also:

• FOOD
• FOOD (like the verb " to feed," from a Teutonic root, whence O. Eng. foda; cf. " fodder "; connected with Gr. lrareicOae, to feed)

food, and also the See also:

• IDIOSYNCRASY (Gr. Ibwavyspavia, peculiar habit of body or temperament; 'lbws, one's own, and viryKpao , blending, tempering, from o-vyiepavvvoOat, to put together, compound, mix)

idiosyncrasy of the individual animal . The oils and fats are distributed throughout the animal and vegetable See also:

• KINGDOM

kingdom from the lowest organism up to the most highly organized forms of animal and vegetable See also:

• LIFE

life, and are found in almost all tissues and See also:

• ORGANS

organs . The vegetable oils and fats occur chiefly in the seeds, where they are stored to nourish the embryo, whereas in animals the oils and fats are enclosed mainly in the cellular tissues of the intestines and of the back . Boiling-point . mm. oC Melting-point . Characteristic of Pressure . C . I . Acids of the Acetic series CnH2nO2 C2H402 76o 119 17 Spindle-See also:

• TREE (0. Eng. treo, treow, cf. Dan. tree, Swed. Odd, tree, trd, timber; allied forms are found in Russ. drevo, Gr. opus, oak, and 36pv, spear, Welsh derw, Irish darog, oak, and Skr. dare, wood)
• TREE, SIR HERBERT BEERBOHM (1853- )

tree oil, See also:

• MACASSAR (MAKASSAR, MANGKASAR)

Macassar oil Acetic acid .

. Butyric acid . C4H802 76o 162.3 -6.5 Butter fat, Macassar oil Isovaleric acid C5H1002 76o 173.7 -51 See also:

• PORPOISE (sometimes spelled Porpus and Porpesse)

Porpoise and See also:

• DOLPHIN

dolphin oils Caproic acid . . 06H1202 770 202-203 -8 Butter fat, coco-nut oil, Caprylic acid . C8H1602 761 236-237 16.5 palm nut oil Capric acid . C1oH2oOz 760 268-270 31.3 pa Lauric acid C12H2402 100 225 43.6 See also:

• LAUREL

Laurel oil, coco-nut oil Myristic acid C14H2802 100 250.5 53.8 Mace butter, See also:

• NUTMEG (from " nut," and O. Fr. mugue, musk, Lat. muscus)

nutmeg butter Isocetic acid (?) C15H3002 •• •• 55 Purging nut Palmitic acid C16Ha20z 100 271.5 62.62 Palm oil, Japan wax, See also:

• MYRTLE

myrtle Stearic acid . C18H3602 See also:

• LOO (formerly called " Lanterloo," Fr. lanturlu, the refrain of a popular 17th-century song)

loo 291 69.32 wax, See also:

• LARD (Fr. lard, from Lat. laridum, bacon fat, related to Gr. Naptvos fat, Napos dainty or sweet)

lard, tallow, &c . Tallow, cacao butter, &c . Arachidic acid . C20H4002 •• .• 77.0 Arachis oil Behenic acid 022H4402 •• .. 83-84 See also:

• BEN (from Old Eng. bennan, within)

Ben oil Lignoceric acid , . . C24H48O2 .. . .

80.5 Arachis oil II . Acids of the Acrylic or Oleic series C,,H2,,-202 C611802 76o 198.5 64.5 Croton oil Tiglic acid Hypogaeic acid . C16Hao02 15 236 33-34 Arachis oil Physetoleic acid . C16H3oO2 .. . . 30 See also:

• CASPIAN

Caspian See also:

• SEAL
• SEAL, FUR
• SEAL, HAIR

seal oil Oleic acid . . C18H3402 100 285.5-286 14 Most oils and fats Rapic acid C,,H3402 •• .. See also:

• RAPE
• RAPE (from Lat. rapere, to seize)
• RAPE (Lat. rapum or rapa, turnip)

Rape oils Erucic acid C22H42O2 3o 281 33-34 Rape oils, See also:

• FISH (O. Eng. fist, a word common to Teutonic languages, cf. Dutch visch, Ger. Fisch, Goth. fisks, cognate with the Lat. piscis)
• FISH, HAMILTON (1808-1893)

fish oils Linolic acid Tariric acid . C18Ha202 .• 50.5 Oil of Picramnia Camboita Telfairic acid . 018H3202 13 220-225 Koeme oil Elaeomargaric acid . C18H3202 •• .. 48 Tung oil IV .

Acids of the cyclic Chaulmoogric series CnH2n—402 Hydnocarpic acid . . C16H2802 59-60 Hydnocarpus, Lukrabo and Chaulmoogric acid . C18H8202 20 247-248 68 Chaulmoogra oils V . Acids of the Linolenic series CH2n-305 C18Hao02 See also:

• LINSEED

Linseed oil Linolenic acid . Isolinolenic acid . . . C18H3002 VI . Acids of the series C,See also:

• H2N

H2n-802 C18H2802 .. . . (liquid) Fish, See also:

• LIVER (O. Eng. lifer; cf. cognate forms, Dutch lever, Ger. Leber, Swed. lefver, &c.; the O. H. Ger. forms are libara, lipora, &c.; the Teut. word has been connected with Gr. i'prap and Lat. jecur)

liver and blubber oils Clupanodonic acid . . . Ricinoleic acid .

See also:

• QUINCE (Lat. Cydonia or Colonea, Ital. Cotogna, Fr. coing, Mid. Eng. coin, quiet, whence a collective plural " quins," corrupted to singular " quince ")

Quince oil acid . C18H3403 .. . . . . Quince oil Dihydroxystearic acid . . . IX . Acids of the series C„H2n-z04 C22H42O4 .. . . 117.7-117.9 Japan wax Japanic acid Up to recently the oils and fats were looked upon as consisting in the See also:

• MAIN (from the Aryan root which appears in " may " and " might," and Lat. magnus, great)
• MAIN (Lat. Moenus)

main of a mixture of triglycerides, in which the three combined fatty acids are identical, as is the case in the above-named glycerides . Such glycerides are termed " See also:

• SIMPLE

simple glycerides." Recently, however, glycerides have been found in which the glycerin is combined with two and even three different acid radicals; examples of such glycerides are distearo-olein, C3H5(O.C18H35O)2, (0.C18H330), and stearo-palmito-olein, C3H5(O•C18H35O) (O•C16H31O) (O•C18H330) . Such glycerides are termed " mixed glycerides." The glycerides occurring in natural oils and fats differ, therefore, in the first instance by the different fatty acids contained in them, and secondly, even if they do contain the same fatty acids, by different proportions of the several simple and mixed glycerides .

Since the methods of preparing the vegetable and animal fats are comparatively crude ones, they usually contain certain impurities of one See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind or another, such as colouring and mucilaginous See also:

• MATTER

matter, remnants of vegetable and animal tissues, &c . For the most See also:

• PART

part these See also:

• FOREIGN

foreign substances can be removed by processes of refining, but even after this See also:

• PURIFICATION

purification they still retain small quantities of foreign substances, such as traces of colouring matters, albuminoid and (or) resinous substances, and other foreign substances, which remain dissolved in the oils and fats, and can only be isolated after saponification of the fat . These foreign substances are comprised in the term "unsaponifiable matter." The most important constituents of the " unsaponifiable matter " are phytosterol C26H430 or C27H440(?), and the isomeric cholesterol . The former occurs in all oils and fats of vegetable origin; the latter is characteristic of all oils and fats of animal origin . This important difference furnishes a method of distinguishing by chemical means vegetable oils and fats from animal oils and fats . This distinction will be made use of in the See also:

• CLASSIFICATION (Lat. classis, a class, probably from the root cal-, cla-, as in Gr. icaMce, clamor)

classification of the oils and fats . A second guiding principle is afforded by the different amounts of See also:

• IODINE (symbol I, atomic weight '26.92)

iodine (see Oil Testing below) the various oils and fats are capable of absorbing . Since this capacity runs parallel with one of the best-known properties of oils and fats, viz. the See also:

• POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power of absorbing larger or smaller quantities of See also:

• OXYGEN (symbol 0, atomic weight 16)

oxygen on exposure to the See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air, we arrive at the following classification: I . FATTY OILS OR LIQUID FATS A . Vegetable oils . B . Animal oils .

1 . Drying oils . 1 . Marine animal oils . 2 . Semi-drying oils . (a) Fish oils . 3 . Non-drying oils . (b) Liver oils (c) Blubber oils . 2 . Terrestrial animal oils .

II . SOLID FATS B . Animal fats . 1 . Drying fats . 2 . Semi-drying fats . 3 . Non-drying fats . Physical Properties.—The specific gravities of oils and fats vary between the limits of 0.910 and 0.975 . The lowest specific gravity is owned by the oils belonging to the rape oil group--from 0.913 to 0.916 . The specific gravities of most non-drying oils See also:

• LIE, JONAS LAURITZ EDEMIL (1833—1908)
• LIE, MARIUS SOPHUS (1842–1899)

lie between 0.916 and 0.920, and of most semi-drying oils between 0.920 and 0.925. whereas the drying oils have specific gravities of about 0.930 .

The animal and vegetable fats possess somewhat higher specific gravities, up to 0.930 . The high specific gravity, 0.970, is owned by See also:

• CASTOR

castor oil and cacao butter, and the highest specific gravity observed hitherto, 0.975, by Japan wax and myrtle wax . In their liquid See also:

• STATE
• STATE, GREAT OFFICERS OF

state oils and fats easily penetrate into the pores of dry substances; on See also:

• PAPER
• PAPER (Fr. papier, from Lat. papyrus)

paper Lhey leave a translucent spot- -"grease spot "—which cannot be removed by washing with water and subsequeLt drying . A curious fact, which may be used for the detection of the minutest quantity of oils and fats, is that camphor crushed between layers of paper without having been torched with the fingers rotates when thrown on clean water, the rotation ceasing immediately when a trace of oil or fat is added such as introduced by touching the water with a See also:

• NEEDLE (O. Eng. ncedl; the word appears in various forms in Teutonic languages, Ger. Nadel, Dutch naal, the root being ne-, to sew, cf. Ger. nahen, and probably Lat. nere, to spin, Gr. vi)ats, spinning)

needle which has been passed previously through the See also:

• HAIR (a word common to Teutonic languages)

hair . The oils and fats are practically insoluble in water . With the exception of castor oil they are insoluble in See also:

• COLD (in O. Eng. cald and ceald, a word coming ultimately from a root cognate with the Lat. gelu, gelidus, and common in the Teutonic languages, which usually have two distinct forms for the substantive and the adjective, cf. Ger. Kolte, kalt, Dutch koude

cold alcohol; in boiling alcohol somewhat larger quantities dissolve . They are completely soluble in See also:

• ETHER, (C2H5)2O

ether, carbon bisulphide, See also:

• CHLOROFORM (trichlor-methane), CHC13

chloroform, carbon tetrachloride, petroleum ether, and See also:

• BENZENE, C6H6

benzene . Oils and fats have no distinct melting or solidifying point . This is not only due to the fact that they are mixtures of several glycerides, but also that even pure glycerides, such as tristearin, exhibit two melting-points, a so-called " See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double melting-point," the triglycerides melting at a certain temperature, then solidifying at a higher temperature to melt again on further See also:

• HEATING

heating . This curious behaviour was looked upon by See also:

• DUFFY, SIR CHARLES GAVAN (1816-1903)

Duffy as being due to the existence of two isomeric modifications, the actual occurrence of which has been proved (1907) in the case of several mixed glycerides . The freezing-points of those oils which are fluid at the ordinary temperature range from a few degrees above zero down to -28° C . (linseed oil) .

At See also:

• LOW, SETH (1850- )
• LOW, WILL HICOK (1853- )

low temperatures solid portions—usually termed ` stearine "—separate out from many oils; in the case of See also:

• COTTON
• COTTON (Fr. coton; from Arab. qutun)
• COTTON, CHARLES (163o–1687)
• COTTON, GEORGE EDWARD LYNCH (1813–1866)
• COTTON, JOHN (1585–1652)
• COTTON, SIR ROBERT BRUCE

cotton-See also:

• SEED (from the root seen in Lat. serere, to sow)

seed oil the separation takes See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place at 12° C . These solid portions can be filtered off, and thus are obtained the commercial " demargarinated oils " or " See also:

• WINTER, JOHN STRANGE
• WINTER, PETER (c. 1755-1825)

winter oils." Oils and fats can be heated to a temperature of 200° to 250° C. without undergoing any material See also:

• CHANGE (derived through the Fr. from the Late Lat. cambium, cambiare, to barter; the ultimate derivation is probably from the root which appears in the Gr. «a urmu', to bend)

change, provided prolonged contact with air is avoided . On being heated above 250° up to 300° some oils, like linseed oil, See also:

• SAFFLOWER (ultimately from the Arabic safra, yellow)

safflower oil, tung oil (See also:

• CHINESE, JAPANESE AND

Chinese or See also:

• JAPANESE

Japanese See also:

• WOOD, ANTHONY A2 (1632-1695)
• WOOD, JOHN GEORGE (1827—1889)
• WOOD, MRS HENRY [ELLEN] (1814—1887)
• WOOD, SEARLES VALENTINE (1798—188o)

wood oil) and even castor oil, undergo a change which is most likely due to polymerization . In the case of castor oil solid products are formed . Above 300° C. all oils and fats are decomposed; this is evidenced by the See also:

• EVOLUTION

evolution of acrolein, which possesses the well-known pungent odour of burning fat . At the same See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time hydro-carbons are formed (see PETROLEUM) . On exposure to the See also:

• ATMOSPHERE (Gr. fir µ6r, vapour; orkaipa, a sphere)

atmosphere, oils and fats gradually undergo certain changes . The drying oils absorb oxygen somewhat rapidly and dry to a film or skin, especially if exposed in a thin layer . Extensive use of this property is made in the paint and See also:

• VARNISH

varnish trades . The semi-drying oils absorb oxygen more slowly than the drying oils, and are, therefore, useless as paint oils . Still, in course of time, they absorb oxygen distinctly enough to become thickened . The property of the semi-dryingoils to absorb oxygen is accelerated by spreading such oils over a large See also:

• SURFACE

surface, notably over woollen or cotton See also:

• FIBRES
• FIBRES (or FIBERS, in American spelling; from Lat. fibra, apparently connected either with filum, thread, or findere, to split)

fibres, when absorption proceeds so rapidly that frequently spontaneous See also:

• COMBUSTION (from the Lat. comburere, to burn up)

combustion will ensue .

Many fires in cotton and woollen See also:

• MILLS, JOHN (d. 1736)
• MILLS, ROGER QUARLES (1832– )

mills have been caused thereby . The non-drying oils, the type of which is olive oil, do not become oxidized readily on exposure to the air, although gradually a change takes place, the oils thickening slightly and acquiring that See also:

• PECULIAR

peculiar disagreeable See also:

• SMELL (connected etymologically with " smoulder " and " smoke ")

smell and acrid See also:

• TASTE (from Lat. taxare, to touch sharply; tangere, to touch)

taste, which are defined by the term " rancid." The changes conditioning rancidity, although not yet fully understood in all details, must be ascribed in the first instance to slow See also:

• HYDROLYSIS (Gr. 6Swp, water, Anew, to loosen)

hydrolysis (" saponification ") of the oils and fats by the moisture of the air, especially if favoured by insolation, when water is taken up by the oils and fats, and See also:

• FREE

free fatty acids are formed . The fatty acids so set free are then more readily attacked by the oxygen of the air, and oxygenated products are formed, which impart to the oils and fats the rancid smell and taste . The products of oxidation are not yet fully known; most likely they consist of See also:

• LOWER

lower fatty acids, such as formic and acetic acids, and perhaps also of See also:

• ALDEHYDES

aldehydes and See also:

• KETONES

ketones . If the fats and oils are well protected from air and See also:

• LIGHT

light, they can be kept indefinitely . In fact C . See also:

• FRIEDEL, CHARLES (1832-1899)

Friedel has found unchanged triglycerides in the fat which had been buried several thousand years ago in the tombs of See also:

• ABYDOS

Abydos . If the See also:

• ACTION

action of air and moisture is allowed free See also:

• PLAY

play, the hydrolysis of the oils and fats may become so See also:

• COMPLETE

complete that only the insoluble fatty acids remain behind, the glycerin being washed away . This is exemplified by See also:

• ADIPOCERE (from the Lat. adeps, fat, and cera, wax)

adipocere, and also by Irish See also:

• BOG (from Ir. and Gael. bogach, bog, soft)

bog butter, which consist chiefly of free fatty acids . The property of oils and fats of being readily hydrolysed is a most important one, and very extensive use of it is made in the arts (See also:

• SOAP

soap-making, See also:

• CANDLE (Lat. candela, from candere, to glow)

candle-making and recovery of their by-products) . If oils and fats are treated with water alone under high pressure (corresponding to a temperature of about 220° C.), or in the presence of water with See also:

• CAUSTIC (Gr. rcavvraubs, burning)

caustic alkalis or alkaline earths or basic metallic oxides (which bodies See also:

• ACT (Lat. actus, actum)

act as " catalysers ") at lower pressures, they are converted in the first instance into free fatty acids and glycerin . If an amount of the bases sufficient to combine subsequently with the fatty acids be present, then the corresponding salts of these fatty acids are formed, such as See also:

• SODIUM [symbol Na, from Lat. natrium; atomic weight 23.00 (0=16)]

sodium salts of fatty acids (hard soap) or See also:

• POTASSIUM [symbol K (from kalium), atomic weight 39.114 0=16)]

potassium salts of the fatty acids (soft soap), soaps of the alkaline See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth (See also:

• LIME
• LIME (O. Eng. lim, Lat. limes, mud, from linere, to smear)

lime soap), or soaps of the metallic oxides (See also:

• ZINC

zinc soap, &c.) .

The See also:

• CONVERSION (Lat. conversio, from convertere, to turn or ,change)

conversion of the glycerides (triglycerides) into fatty acids and glycerin must be looked upon as a reaction which takes place in stages, one molecule of a triglyceride being converted first into diglyceride and one molecule of fatty acid, the diglyceride then being changed into monoglyceride, and a second molecule of fatty acid, and finally the monoglyceride being converted into one molecule of fatty acid and glycerin . All these reactions take place concurrently, so that one molecule of a diglyceride may still retain its ephemeral existence, whilst another molecule is already broken up completely into free fatty acids and glycerin . The oils and fats used in the See also:

• INDUSTRIES

industries are not See also:

• DRAWN

drawn from any very See also:

• GREAT

great number of See also:

• SOURCES

sources . The tables on the following pages contain chiefly the most important oils and fats together with their sources, yields and See also:

• PRINCIPAL

principal uses, arranged according to the above classification, and according to the magnitude of the iodine value . It should be added that many other oils and fats are only waiting improved conditions of transport to enter into successful competition with some of those that are already on the See also:

• MARKET (Lat. mercatus, trade or place of trade)

market . Extraction.—Since the oils and fats have always served the human race as one of the most important articles of food, the oil and fat See also:

• INDUSTRY (Lat. industria, from indu-, a form of the pre, position in, and either stare, to stand, or struere, to pile up)

industry may well be considered to be as old as the human race itself . The methods of preparing oils and fats range themselves under three heads: (r) Extraction of oil by " rendering," i.e. boiling out with water; (2) Extraction of oil by expression; (3) Extraction of oil by means of solvents . Rendering.—The crudest method of rendering oils from seeds, still practised in Central See also:

• AFRICA
• AFRICA, ROMAN

Africa, in Indo-See also:

• CHINA

China and on some of the See also:

• SOUTH
• SOUTH, ROBERT (1634–1716)

South See also:

• SEA (in O. Eng. sae, a common Teutonic word; cf. Ger. See, Dutch Zee, &c.; the ultimate source is uncertain)
• SEA, COMMAND OF THE

Sea Islands, consists in heaping up oleaginous fruits and allowing them to melt by the See also:

• HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

heat of the See also:

• SUN
• SUN (0. Eng. sonne, Ger. sonne. Fr. soleil, Lat. sol, Gr. ijXior, from which comes helio- in various English compounds)

sun, when the exuding oil runs off and is collected . In a somewhat improved form this See also:

• PROCESS

process of rendering is practised in the preparation of palm oil, and the rendering the best (See also:

• COCHIN
• COCHIN, DENYS MARIE PIERRE AUGUSTIN (1851L'Evolution de la vie (1895); Le Monde exterieur (1845); Contre les barbares (1899)

Cochin) coco-nut oil by boiling the fresh kernels with water . Since hardly any machinery, or only the simplest machinery, is required for these processes, this method has some See also:

• FASCINATION (from Lat. fascinare, to bewitch, probably connected with the Or. f3ao-Kaiveev, to speak ill of, to bewitch)

fascination for A . Vegetable fats . inventors, and even at the present See also:

• DAY (O. Eng. dreg, Ger. Tag; according to the New English Dictionary, " in no way related to the Lat. dies")
• DAY, JOHN (1574-1640?)
• DAY, THOMAS (1748-1789)

day processes are being patented, having for their See also:

• OBJECT

object the boiling out of fruits with water or See also:

• SALT (a common Teutonic word, cf. Dutch zout, Ger. Salz, Scand. salt; cognate with Gr. &Xs, Lat. sal)
• SALT, SIR TITUS, BART

salt solutions, so as to facilitate the separation of the oil from the pulp by See also:

• GRAVITATION (from Lat. gravis, heavy)

gravitation .

Naturally these processes can only be applied tb those seeds which contain large quantities of fatty matter, such as coconuts and See also:

• OLIVES, MOUNT OF, or MOUNT OLIVET ("Opus 'EXc uwos or riov 'EXauav; mod. Jebel-et-Tur)

olives . The rendering process is, however, applied on a very large See also:

• SCALE
• SCALE (1) A

scale to the See also:

• PRODUCTION (Lat. productionem, from producere, to pro-duce)

production of animal oils and fats, Formerly the animal oils and fats were obtained by heating the tissues containing the oils or fats over a free See also:

• FIRE (in O. Eng. f j'r; the word is common to West German languages, cf. Dutch vuur, Ger. Feuer; the pre-Teutonic form is seen in Sanskrit pu, pavaka, and Gr. irup; the ultimate origin is usually taken to be a root meaning to purify, cf. Lat. purus)

fire, when the See also:

• CELL (from Lat. cella, probably from an Indo-European kal —seen in Lat. celare, to hide; another suggestion connects the word with Lat. cera, wax, taking the original meaning to refer to the honeycomb)

cell membranes burst and the liquid fat flowed out . The See also:

• CAVE (Lat. cavea, from caves, hollow)
• CAVE, EDWARD (1691–1754)
• CAVE, WILLIAM (1637–1713)

cave-dweller who first collected the fat dripping off the See also:

• DEER (O. E. rigor, dfor, a common Teutonic word, meaning a wild animal, cf. Ger. Tier, Du. dier, &c., probably from a root dhus-, to breathe)
• DEER, CHINESE

deer on the roasting See also:

• SPIT

spit may well be looked upon as the first manufacturer of tallow . This crude process is now classed amongst the noxious trades, owing to the offensive stench given off, and must be considered as almost See also:

• EXTINCT

extinct in this country .