Chapter XXV: Front Matter (25)

=OILS (Medicated).= _Syn._ OLEA COCTA, O. INFUSA, O. MEDICATA, L. These are prepared by infusion or decoction. The bruised ingredients are either simply digested in 2 to 4 times their weight of olive oil for some days, or they are gently boiled in it until they become dry and crisp, great care being taken that the heat towards the end of the process is not greater than that of boiling water. As soon as the process is complete, the oil is allowed to drain from the ingredients, which are then (if necessary) submitted to the action of the press. The product is commonly run through flannel or a hair sieve whilst still warm, after which it is allowed to repose for a week or ten days, when the clear portion is decanted from the dregs. The green or recent plants are usually employed for this purpose, but, in many cases, the dried plants, reduced to powder, and digested for 6 or 8 hours in the oil, at the heat of hot water, with frequent agitation, yield a much more valuable product. They are nearly all employed as external applications only.

⁂ The following are the most important preparations of this class:——

=Oil of Adder’s Tongue.= _Syn._ OLEUM OPHIO GLOSSI, L. From the herb, as OIL OF BELLADONNA. A popular vulnerary.

=Oil of Ants.= _Syn._ OLEUM FORMICARUM. Digest 4 oz. of ants in 16 oz. (by weight) of olive oil with a gentle heat, and strain.

=Oil of Bal′sam Apple.= _Syn._ OLEUM BALSAMINÆ. _Prep._ Balsam apple (deprived of seeds), 1 oz.; oil of almonds, 4 oz.; digest and strain.

=Oil of Belladon′na.= _Syn._ OLEUM BELLADONNÆ (P. Cod.), L. _Prep._ From the fresh leaves, bruised, 1 part; olive oil, 4 parts; digested together at a gentle heat until the moisture is evaporated; the oil is then strained off with pressure, and filtered.

=Oil of Cantha′rides.= _Syn._ OLEUM CANTHARIDIS, O. CANTHARIDIBUS, L. _Prep._ (P. Cod. 1839). From Spanish flies (powdered), 1 part; olive oil, 8 parts; as OIL OF BELLADONNA. Stimulant and rubefacient. Used as a dressing to indolent sores, blisters, &c.; and in dropsy, rheumatism, gout, &c., OIL OF THE OIL-BEETLE (_Meloe proscarabæus_——Linn.) is prepared in a similar manner.

=Oil of Cap′sicum.= _Syn._ OLEUM CAPSICI, L. _Prep._ (Dr Turnbull.) From powdered capsicum or Cayenne pepper, 4 oz., olive oil, 1 pint; digested together for 6 hours, with heat, and strained. Stimulant; rubefacient in colic, cholera, &c.

=Oil of Cham′omile.= _Syn._ OLEUM ANTHEMIDIS, OL. CHAMÆMELI, L. From the dried flowers (rubbed to pieces), 1 part, olive oil, 8 parts; digested together, with heat, for 6 hours. Stimulant, emollient, and vermifuge.

=Oil of Col′ocynth.= _Syn._ OLEUM COLOCYNTHIDIS, L. From the pulp, as OIL OF CHAMOMILE. Diuretic. In dropsy, neuralgia, rheumatism, worms, &c.

=Oil of Earth′worms.= _Syn._ OLEUM LUMBRICORUM. (E. Ph. 1744.) Washed earthworms, 1/2 lb.; olive oil, 1-1/2 pint; white wine, 1/2 pint. Boil gently till the wine is consumed, and press and strain.

=Oil of Elder-flowers.= _Syn._ WHITE OIL OF ELDER; OLEUM SAMBUCI ALBUM, O. SAMBUCINUM (P. Cod.), L. _Prep._ From the flowers, as OIL OF CHAMOMILE. Emollient and discussive.

=Oil of Elder-leaves.= _Syn._ GREEN OIL, GREEN OIL OF ELDER, OIL OF SWALLOWS; OLEUM VIRIDE, O. SAMBUCI VIRIDE, L. _Prep._ 1. Green elder leaves, 1 lb.; olive oil, 1 quart; boil gently until the leaves are crisp, press out the oil, and again heat it till it turns green.

2. As before, but by maceration, at a heat under 212° Fahr. More odorous than the last.

3. Elder leaves, 1 cwt.; linseed oil, 3 cwt.; as No. 1.

_Obs._ The last form is the one usually employed on the large scale. It is generally coloured with verdigris, 1/2 lb. to the cwt., just before putting it into the casks, and whilst still warm; as, without great skill and a very large quantity of leaves, the deep-green colour so much admired by the ignorant cannot be given to it. The oil is got from the leaves by allowing them to drain in the pan or boiler (with a cock at the bottom), kept well heated. Emollient; in great repute among the vulgar as a liniment, in a variety of affections.

=Oil of Fen′ugreek.= _Syn._ OLEUM FŒNUGRÆCI, L. _Prep._ (P. Cod.) From the seeds, as OIL OF CANTHARIDES or of CHAMOMILE. Emollient and resolvent.

=Oil of Fox′glove.= _Syn._ OLEUM DIGITALIS, L. _Prep._ (P. Cod.) From the fresh leaves, as OIL OF BELLADONNA. Used as an application to chronic ulcers and indurations, painful swellings &c. As usually met with, it is nearly inert.

=Oil of Garden Night′shade.= _Syn._ OLEUM SOLANI, L. _Prep._ (P. Cod.) From the leaves, as OIL OF BELLADONNA. Anodyne and discussive.

=Oil of Gar′lic.= _Syn._ OLEUM ALLII INFUSUM, L. From garlic, as OIL OF BELLADONNA. Used as a liniment in deafness, diarrhœa, infantile convulsions, palsy, rheumatism, &c.

=Oil, Green.= _Syn._ OLEUM VIRIDI, L. From bay leaves, origanum, rue, sea wormwood, and elder leaves, of each 2-1/2 oz.; olive oil, 1 quart; as OIL OF ELDER. Detergent, stimulant, and resolvent. Green oil of elder is now usually sold for it.

=Oil of Hem′lock.= _Syn._ OLEUM CONII, L. _Prep._ (P. Cod.) As OIL OF BELLADONNA. Anodyne and emollient; in painful ulcers, glandular tumours, &c.

=Oil of Hen′bane.= _Syn._ OLEUM HYOSCYAMI, L. _Prep._ (P. Cod.) As OIL OF BELLADONNA. Used as the last, in various painful local affections.

=Oil Iodizeo, Marshall’s.= _Syn._ OLEUM IODATUM. _Prep._ Oil of almonds, 15 parts; iodine, 1 part. Triturate and digest till dissolved.

=Oil of Ju′′niper (by Infusion).= _Syn._ OLEUM JUNIPERI INFUSUM, L. From the crushed berries, as OIL OF BELLADONNA. Diuretic and vulnerary; in frictions, &c.

=Oil of Lil′ies.= _Syn._ OLEUM LILIORUM, L. From white lilies, 1 lb.; olive oil, 3 lbs.; as OIL OF BELLADONNA. Emollient; used to soften and ripen tumours, indurations, &c.

=Oil of Mel′ilot.= _Syn._ OLEUM MELILOTI, L. As the last, avoiding much heat. Emollient and resolvent.

=Oil of Mu′cilages.= _Syn._ OLEUM MUCILAGINUM, O. CUM MUCILAGINIBUS, L. _Prep._ 1. (Ph. L. 1746.) Marshmallow root, 1/2 lb.; linseed and fenugreek seed, of each, bruised, 3 oz.; water, 1 quart; boil 1 hour, add of olive oil, 2 quarts, and boil until the water is consumed.

2. Fenugreek seeds, 8 oz.; linseed oil, 1 quart; infuse a week, and strain. Once a highly popular emollient application in various local affections.

=Oil of Mu′dar.= _Syn._ OLEUM MUDARIS, L. From mudar bark (in coarse powder), 1 dr.; warm olive oil, 1/4 pint; digest 24 hours and strain. Used as an application to cutaneous ulcers, the bites of venomous animals, &c., and as a friction in worms.

=Oil of O′′pium.= _Syn._ ANODYNE OIL, OPIATED O.; OLEUM OPIATUM, L. _Prep._ From opium (in powder), 1 dr.; olive oil, 2-1/2 fl. oz.; digest at a gentle heat, with frequent agitation, for 5 or 6 hours. The powder should be rubbed in a mortar with a few drops of the oil before adding the remainder. As a local anodyne. The above is the only reliable formula for this preparation. Others are extant, but whilst the products of several are much stronger, those from others have only 1-5th or 1-6th the strength.

=Oils, Ozonised.= (Dr Thompson.) _Syn._ OLEO OZONATA. _Prep._ Pass oxygen gas into the oil (cocoa nut, sunflower, cod-liver oil, &c.) until it will dissolve no more. Then expose for a considerable time in the direct rays of the sun. Used in phthisis.

=Oil of Pel′litory.= _Syn._ OLEUM PYRETHRI, L. From bruised pellitory root, as OIL OF BELLADONNA. Used as the last.

=Oil of Black Pep′per (by Infusion).= _Syn._ OLEUM PIPERIS INFUSUM, L. From black pepper, in coarse powder, as OIL OF CAPSICUM. Stimulant and rubefacient; in frictions.

=Oil of Poison Oak.= _Syn._ OLEUM RHOIS TOXICODENDRI, L. From the leaves, as OIL OF BELLADONNA Externally; in paralysis, &c.

=Oil of Rhu′barb.= _Syn._ OLEUM RHEI, L. From rhubarb (in powder), 1 part; oil of almonds, 8 parts; digested together in a gentle heat for 4 hours, and strained, with expression. As an application to indolent ulcers, and as a friction over the abdomen in diarrhœa, English cholera, &c., or as a laxative when the stomach will not bear medicine.

=Oil of Ro′′ses.= _Syn._ OLEUM ROSÆ, O. ROSACEUM, O. R. INFUSUM, O. ROSATUM, L. _Prep._ From the fresh petals, pulled to pieces, crushed, and digested for 2 or 3 days in the sun, or a warm situation, in 4 times their weight of olive oil, and then pressed; the process being repeated with fresh roses. Ph. E. 1744 and P. Cod. are nearly similar. ALMOND, BEN, or OLIVE OIL, coloured with ALKANET, and scented with attar of roses, is now almost universally sold for it. Used for the hair.

=Oil of Rue.= _Syn._ OLEUM RUTÆ (INFUSUM), L. _Prep._ (P. Cod.) From fresh rue, bruised, as OIL OF CHAMOMILE. Reputed antispasmodic, emmenagogue, stimulant, and vermifuge. In frictions.

=Oil of St John’s Wort.= _Syn._ OLEUM HYPERICI (Ph. L. 1746), O. H. SIMPLEX, BALSAMUM H., L. From the flowers, 1 part; olive oil, 6 parts; digested together until the oil is well coloured. Antispasmodic, stimulant, and resolvent. A mixture of equal parts of RAPE OIL and GREEN ELDER OIL is usually sold for it.

=Oil of Scam′mony.= _Syn._ OLEUM SCAMMONII, O. PURGANS, L. _Prep._ (Van Mons.) From scammony (in powder), 1 dr.; hot oil of almonds, 3 fl. oz.; triturate together until cold, and the next day decant the clear portion.——_Dose_, 1/2 to 1 table-spoonful.

=Oil of Stramo′′nium.= _Syn._ OLEUM STRAMONII, L. _Prep._ (P. Cod.) From the leaves of thorn apple or stramonium, as OIL OF BELLADONNA. Anodyne and discussive; as an application to painful tumours, joints, &c.

=Oil of Tobac′co (by Infusion).= _Syn._ OLEUM TABACI, O. T. INFUSUM, L. From fresh tobacco leaves (bruised), like OIL OF CHAMOMILE. As an application in ringworm, irritable ulcers, pediculi, &c.; and as a friction in itch, neuralgia, painful indurations, &c. It must be used with extreme caution, as it is poisonous.

=Oil of Tooth′wort.= _Syn._ OLEUM SQUAMARIÆ, L. From the herb of _Lathræa squamaria_ (Linn.), as OIL OF ST JOHN’S WORT. Astringent and vulnerary. This must not be confounded with another preparation sometimes called ‘OIL OF TOOTHWORT’ (OLEUM PLUMBAGINIS EUROPÆÆ),and which has been occasionally used in itch, as the latter is acrid and apt to cause much irritation.

=Oil of Worm′wood.= _Syn._ OLEUM ABSINTHII, L. From the fresh herb, as OIL OF LILIES. The P. Cod. and Ph. Wurtem. order only part of the herb to 8 parts of oil. Applied to the abdomen in dyspepsia, diarrhœa, heartburn, worms, &c. It is seldom used in this country.

=OILS (Mineral).= _Syn._ HYDROCARBON OILS. An important class of liquids, consisting solely of carbon and hydrogen——the elements of ordinary coal-gas, and obtained by the distillation of coal, lignite, petroleum, and other bituminous substances. For the purposes of illumination, many of these oils are in most respects superior to the fixed or fat oils containing oxygen. They give a whiter and more brilliant light, and are produced at a much lower cost. The lamps in which they are burnt, when properly constructed, are less liable to get out of order than those adapted for the combustion of fat oils, and require less attention when in use. The experiments of Dr Frankland on the relative value of the ordinary illuminating agents[57] prove that the mineral oils are cheaper than all other portable illuminating agents in common use, and that they give, while burning, the largest amount of light with the least development of heat, and the smallest production of carbonic acid. With the oils adapted for burning in lamps other oils are produced. Some are very volatile and highly inflammable, and the safety of the burning oils depends on their proper extraction. These volatile liquids, when isolated, are used in the arts as substitutes for spirits of turpentine, as solvents for various substances, and to increase the illuminating power of coal-gas. Others are of a greasy nature, and are too heavy to be conveniently used in lamps. These, however, are well adapted for lubricating fine machinery, and are extensively employed instead of sperm oil by the cotton manufacturers of Lancashire. When the more volatile ingredients are separated from the burning oils, the latter are perfectly safe. Most of the mineral burning oils now in use are, we believe, free from danger in this respect. (See _Tests_, _below_.)

[Footnote 57: See article ILLUMINATION.]

_Hist._ For many years the manufacture of burning oils by the distillation of bituminous schists has been extensively carried out on the Continent, but the discovery which formed the foundation of the modern manufacture was made nearly thirty years ago by our countryman, Mr James Young. This gentleman took the lease of a spring of petroleum in 1847, and after numerous experiments succeeded in obtaining two useful oils from the crude liquid; the one being adapted for lubricating machinery, and the other for burning in lamps. The almost total cessation of the flow of petroleum terminated the business after two years’ working, and led Mr Young to institute a series of experiments to try if petroleum could be produced artificially by the destructive distillation of coal. These experiments resulted in the discovery of an oil which Mr Young named ‘Paraffin oil,’ as it had many of the chemical properties of the solid body of paraffin, discovered twenty years before by Reichenbach in beech-wood tar. Young’s patent (dated Oct. 7, 1850) involved the slower distillation of coals, at a lower temperature than had hitherto been employed for the purpose, and this novelty in practice was followed by the novel result of a copious production of liquid hydrocarbons. The gas or cannel coals were found to yield the liquids in largest quantities, that variety known as Boghead coal or Torbane Hill[58] mineral being specially adapted for the patented process. (See PARAFFIN OIL, _below_.) Soon after Young’s discovery native petroleum was brought from Rangoon, and purified by distillation, so as to produce oils very similar to the coal products. During the last few years, however, rich sources of petroleum have been discovered in North America, and from whence are imported the greater part of the vast quantities of petroleum oil (both for burning and lubricating purposes), together with the paraffin spirit, or naphtha, which are consumed in this country.

[Footnote 58: This species of coal is now exhausted.——ED.]

In the following table are given the quantities of these substances sent into England and Scotland during the year 1875:——

+---------+---------------+----------------+---------+-----------------+
| |Refined burning|Lubricating Oil.|Residuum.|Petroleum Spirit.|
| | Oil. | | | |
+---------+--------+------+----------------+---------+-------+---------+
| |Barrels.|Cases.|Barls. & Casks. |Barrels. |Cases. |Barrels. |
|London | 169,762| 3,250| 2,511 | 1,000 | ... | 53,173 |
|Liverpool| 95,853| 2,830| 300 | 29,358 | ... | 30,913 |
|Hull | 20,226| 8| ... | ... | ... | ... |
|Bristol | 36,889| 1,392| ... | ... | ... | 17,203 |
|Clyde and| | | | | | |
| Leith | 4,233| 4| 535 | 9,387 | ... | ... |
+---------+--------+------+----------------+---------+-------+---------+
| Total | 326,963| 7,484| 3,346 | 39,745 | ... |101,289 |
+---------+--------+------+----------------+---------+-------+---------+

This amounts to about 17 millions of gallons. In 1874 it exceeded 20 millions of gallons, but the stock in hand at the end of 1874 was about 5 millions of gallons, and the end of 1875 was only 1-1/2 million. The difference was mainly due to overtrading in 1874, which brought refined petroleum to the lowest price yet known in England, viz. 7-3/4d. per gallon in December, 1874, and checked its subsequent importation.[59]

[Footnote 59: W. Matthieu Williams.]

_Tests, Precautions._ The Sanitary Commission of the ‘Lancet’ took as the limit of safety an oil that gave off inflammable vapour when heated to 130° Fahr., and this has been generally accepted by dealers. If an oil gives off inflammable vapours before being heated up to 130°, it is considered unsafe for domestic use.

1. The plan for testing this, recommended in the ‘Lancet,’ is to heat a portion of the suspected oil in a gallipot placed in boiling water, ascertaining by a thermometer suspended in the oil the temperature at which it will take fire on the surface when a lighted wax vesta is applied to it. This is a troublesome and dangerous process, and has little practical value.

2. A rough-and-ready method of testing the inflammability of a sample is to pour a little out on a dry flat board, and try whether it can be ignited readily by a lighted paper. If it catches fire like turpentine or brandy, the oil is dangerous.

3. The following plan, proposed by Mr Tegetmeier, requires no scientific knowledge and no apparatus but what is to be found in every house, while it is sufficiently accurate for all practical purposes:——

“Take an earthenware dish, holding about half a pint (a breakfast cup will do), fill the cup full from a kettle of boiling water, pour this into an earthenware quart jug, then fill the same cup again with boiling water from the kettle, and pour it also into the quart jug, then fill the cup with cold water, put it into the jug, shake the jug to mix the hot and cold water, then pour the tepid water from the jug into the cup till the cup is half full, then pour about a table-spoonful of the oil to be tested on the tepid water in the cup, take the oil-can with the oil out of the room, then touch the surface of the oil in the cup with a lighted splinter of wood, or a match without sulphur. If the match causes a flash of flame to appear on the surface of the oil, the oil is below the standard of safety, and should not be used; if no flame appears, the oil is up to the standard. We may mention that in this trial no time should be lost after pouring the boiling water from the kettle, as the water may get too cold, but the whole may be gone through in from two to three minutes. It is well to have a saucer at hand, and if the oil should be a bad oil, and ignite with the match, place the saucer on the mouth of the cup, and the flame is extinguished. This trial should be done by daylight, and at a distance from a fire, and the directions must be followed exactly in the order as given above.”

4. Provided that the oils to be examined have been produced by careful fractional distillation, their relative volatility, as indicated by their specific gravity, shows to a great extent the facility with which they ignite. The lightest oils are more volatile and more easily inflamed than those which are heavier. Oils much under ·800 inflame directly a lighted match is thrown into them, whereas oils at about ·815 to ·823 (if unmixed products) cannot be set on fire in this manner. The specific gravity test cannot, however, be depended on to determine the inflaming point of any commercial oil. A heavy oil, badly rectified, may contain a proportion of very volatile vapour, and have a low inflaming point; whereas a much lighter oil may be perfectly safe, from its having the more volatile portions carefully removed.

5. (Van der Weyde.) The oil to be tested is placed in a graduated tube closed at one end; the open end is then closed with the finger, and is then placed mouth downwards in a vessel of water that is heated from 43°——44° C. The vapour from the portion volatilised at this temperature then collects in the upper part of this tube, and expels a corresponding quantity of oil. See PETROLEUM.

In Great Britain petroleum is defined by Act of Parliament as being any oil which gives off all inflammable vapour at a temperature less than 100° F.

To prevent accidents with paraffin or petroleum lamps, the following precautions ought to be observed:——

The lamps should be filled and trimmed by daylight.

They should never be overfilled; the oil should not be allowed to come into contact with the metal work of the burner.

Any portion of oil spilled on the outside of the lamp should be carefully wiped away.

When not in use the wick should be turned down into the wick-holder.

⁂ The principal products noticed below rank high among the numerous varieties of mineral oil now in the market, but there are doubtless many others equally good and safe. Their properties are described in accordance with the results obtained by Mr W. B. Tegetmeier, who has devoted much time to the examination of the mineral oils:——

=Oil, Al′bertite.= From ‘Albertite,’ a lustrous black mineral found in New Brunswick. A sample was shown in the Colonial Department of the International Exhibition of 1862, but the oil has not yet appeared in the English market.

_Prop._ Odour very slight; illuminating power high; boiling point 338° Fahr., or 126° above that of water.

=Oil, American.= See PETROLEUM OIL (_below_).

=Oil, Apyroec′tic.= _Syn._ NON-EXPLOSIVE OIL. A burning oil, introduced by F. Tall, of Hull, and prepared, we believe, from American petroleum.

_Prop._ Slightly coloured; perfectly limpid; odour slight, but not perceivable during combustion. The most remarkable property of this oil is that, in spite of its limpidity, the point at which it gives off inflammable vapour is 180° Fahr., or 80° above the requirements of the Petroleum Act.

=Oil, Bel′montine.= From Rangoon tar, or Burmese petroleum, by distillation; superheated steam being employed as the heating agent.

_Prop._ Colourless; odour not unpleasant; sp. gr. ·847; but although so heavy, the oil is altogether free from viscosity, and will rise rapidly in a comparatively long wick; inflaming point 134° Fahr.; burns with an exceedingly white light, and possesses a very high illuminating power.

_Obs._ The distillation of the Rangoon tar is carried on by Price’s Patent Candle Company under a patent. Besides the above lamp oil, several beautiful and useful products are obtained. At first there comes over a very volatile liquid, termed SHERWOOD OIL, used as a detergent for removing grease from fabrics, cleaning gloves, &c.; then comes the BELMONTINE OIL, already noticed; then two lubricating oils, the one light and the other heavy; and, last of all, when the temperature is considerably elevated, the beautiful white, translucent solid known as BELMONTINE, distils over. This last is a kind of paraffin, and is used for making ornamental candles.

=Oil, Caz′eline.= An excellent burning oil, probably prepared from American petroleum, introduced by Cassell, Smith, and Co., of London.

_Prop._ Bright, limpid, with scarcely a trace of colour; odour very slight, and quite free from any objectionable character; sp. gr. ·805; lowest point of ignition 144° Fahr.; burns with a pure white light, free from smoke and smell.

=Oil, Col′zarine.= A heavy hydrocarbon oil, adapted for burning in lamps constructed from the old ‘Moderators’ and ‘Carcels,’ formerly so much used for the fat oils.

_Prop._ Limpid; quite inodorous; of a pale amber colour; sp. gr. about ·838; temperature at which the vapour can be permanently ignited, 250° Fahr. Tested in the altered moderator, it gives an intense white light, without smoke or smell. Compared with vegetable colza oil, its illuminating power is in the proportion of 3 to 2.

_Obs._ This oil is manufactured by Cassell, Smith, and Co., under Martin’s patent for the modification of mineral oils, to fit them for burning in lamps where ‘colza’ and other vegetable and animal oils have been usually consumed. Similar oils are prepared by other firms.

=Oil, Machin′ery.= _Syn._ LUBRICATING OIL, SHAFTING O., SPINDLE O. The heavier hydrocarbon, oils obtained in distilling coal, shale, and petroleum, have almost superseded the fat oils for lubricating purposes. They have no chemical action on the ordinary metals, and are not affected by cold. The lightest of these comparatively heavy oils are used for spindles, or other kinds of rapid machinery; the heaviest for the bearing parts of heavy machinery; and those of an intermediate character for such things as printing-presses, agricultural steam-engines, &c. In America and on the Continent this oil is also used for making gas. The firm of Whitmore and Craddock is favorably known for the manufacture and purification of these machinery oils. See OIL, BELMONTINE (_above_), and OIL, PARAFFIN (_below_).

=Oil, Pa′raffin.= _Syn._ PARAFFINE OIL. This name was given by Mr Young to the oil produced by the distillation of cannel coal, Boghead coal, &c., at a temperature considerably lower than that employed in the manufacture of illuminating gas. The following is a brief outline of Mr Young’s process:——

_Manuf._ (Young’s patent.) Boghead coal, broken into small fragments, is introduced into perpendicular tubes or retorts, about eleven feet in height, by conical hoppers at their upper extremities. Four of these tubes constitute a set, being built into one furnace, and charged by a single workman. They pass completely through the furnace, and are closed below by dipping into shallow pools of water, while the openings into the hoppers above may be shut by spherical valves. The coal in each tube is gradually heated as it descends to that part which passes through the furnace, and when it reaches the bottom of the tube it has parted with its volatile constituents, and is raked away as refuse, the coal from above descending as it is removed. Thus, the action of these perpendicular retorts is continuous, and the distillation goes on uninterruptedly both day and night. The vapours produced are conducted by iron tubes to the main condensers, which consist of a series of syphon pipes freely exposed to the air. The quantity of incondensible gas formed is inconsiderable; and it is this result, so different from that obtained in the ordinary gasworks, that marks the great value of Young’s process. The crude oil, a dark-coloured, thick liquid, is then distilled to dryness in large iron cylindrical stills, and is thus freed from the excess of carbon which is left behind as coke. The oil, after distillation, is further purified by being acted upon by strong sulphuric acid (oil of vitriol), which chars the principal impurities, and causes them to subside in the form of a dense black, heavy acid tar. To separate the remaining impurities, and that portion of the sulphuric acid which remains in the oil, it is next subjected to the action of caustic soda. As thus purified, the paraffin oil contains four distinct commercial products. To effect their separation, the process of fractional distillation is first employed. The first elevation of temperature drives over the lighter and more volatile portions, which, when purified by a subsequent distillation, yields the fluid known as ‘paraffin naphtha,’ ‘petroleum spirit,’ ‘benzoline.’ This product is used as a substitute for ‘turps,’ as a solvent for india rubber for cleaning gloves, and for burning in those naphtha lamps so much employed by costermongers, and workmen in railway tunnels and similar situations. On the perfect separation of this naphtha the safety of the burning oil depends. This burning oil, the ‘paraffin oil’ of commerce, comes over at a much higher temperature than the naphtha. It is a perfectly safe lamp oil, and has a greater illuminating value than any other oil in the market. Its properties are noticed _below_. The third product in point of volatility is a comparatively heavy liquid (machinery oil), largely used for lubricating purposes in the Lancashire factories. From this oil, and others which come over at a very high temperature, the fourth commercial product is separated by the action of artificial cold. This last product is the beautiful translucent solid, paraffin, now much used as a candle material.[60] (See OIL, PARAFFIN, PETROLEUM.)

[Footnote 60: For a detailed account of the processes carried on at the Bathgate works, see Mr Tegetmeier’s paper in ‘England’s Workshops,’——Groombridge and Sons.]

In the preparation of paraffin oil, from native petroleum, the oil is obtained by direct distillation from the petroleum, and subsequently separated from the more or less volatile hydrocarbons (the paraffin naphtha, the lubricating oils and the solid paraffin) that are associated with it by fractional distillation as in Young’s process; whereas, when procured from bituminous minerals, it is derived from the _tar_ or _crude oil_, which has to be previously extracted from the bituminous matters by destructive distillation. There are various methods for obtaining this tar or crude oil, which, although differing in detail, are in general principles very similar to that described in Young’s patent. Thus, whilst in many works _closed_ horizontal retorts are employed, in other establishments vertical ones, to the bottoms of which are attached receptacles for the receipt of the exhausted coal or other material as it falls from the retort, the same as in Young’s apparatus, are extensively adopted. When horizontal retorts are employed they are made of cast iron, and vary in length from 8 to 10 feet, being from 28 to 34 inches wide and from 9 to 14 inches deep. The charge is introduced by an opening in the end of the retort, by which aperture the exhausted residue is removed when necessary. This aperture is closed by a tightly fitting cast iron cover while the distillation is going on. At the other end of the retort is a pipe for carrying off the products of distillation. This communicates with a larger pipe, and this latter with the condensing apparatus. A number of these retorts are set together in a row, with a furnace at one end, and flues extending beneath the retorts, while the upper parts of the retorts are covered with brickwork, to prevent the oil vapours from being decomposed by the heat of the waste furnace gas passing to the chimney through the flues above the retorts.

The gaseous products of the distillation of the tar, leaving the retort by the exit tube already described, are cooled by being made to pass through a number of iron pipes exposed to the air, or surrounded by water, and thus becoming condensed pass into a reservoir in the form of the oil, which forms the material from which the various hydrocarbons are separated by fractional distillation. Accompanying the oil vapours are certain uncondensable gases; these escape through a properly contrived outlet which is made in the condensing pipes; in some works these escaping gases are utilised as fuel, and in others for purposes of illumination.

In other works superheated steam is driven into the retorts during the process of distillation; but although this has the effect of sweeping the oil vapour more quickly out of the retort into the condenser, it is questionable whether this advantage covers the extra cost of the production of the steam.[61]

[Footnote 61: Payne’s ‘Industrial Chemistry.’ Edited by Dr Paul.]

In many parts of Germany the extraction of the crude oil or tar from bituminous substances is effected in ovens. In these ovens the bituminous body is thrown upon a layer of burning fuel which covers the bottom of the oven, the result being that the bituminous matter is resolved into gaseous bodies which are lost, and tar which flows downwards toward the burning fuel, which being covered with a layer of clay is prevented from entering into violent combustion. This method, however, is only had recourse to on a small scale, since it is found that in most cases the tar obtained by means of it is not of a kind suited for yielding paraffin and paraffin oils.

The preparation of the tar or crude oil from fossil fuel, of the character already specified, constitutes one of the most delicate and difficult branches in the manufacture of paraffin oils, and paraffin, &c. The chief sources of failure to be avoided are the overheating of the oil vapour, and its consequent decomposition (varying in amount) into useless gaseous products; and its inefficient condensation.

It has been shown by Vohl that even when the construction of the retorts is not of the best, an average yield of tar may be obtained by the proper condensation of the vapours. “The complete condensation of the vapours of the tar is one of the most difficult problems the mineral oil and paraffin manufacturer has to deal with, while the means usually adopted for condensation, such as large condensing surfaces, injection of cold water, and the like, have proved ineffectual. It has often been attempted to condense the vapours of tar in the same manner as those of alcohol, but there exist essential differences between the distillation of fluids and dry distillation. In the former case the vapours soon expel all the air completely from the still and from the condenser, and provided, therefore, that, in reference to the size of the still and bulk of the boiling liquid, the latter be large and cool enough, every part of the vapour must come into contact with the condensing surfaces. In the process of dry distillation the process is entirely different, because with the vapours, say of tar, permanent gases are always generated. On coming into contact with the condensing surfaces a portion of the vapours is liquefied, leaving a layer of gas as a coating, as it were, on the condensing surface. The gas being a bad conductor of heat prevents to such an extent the further action of the condensing apparatus, that a large proportion of the vapours are carried on, and may be altogether lost. A sufficient condensation of the vapours of tar can be obtained only by bringing all the particles of matter which are carried off from the retorts into contact with the condensing surface, which need neither be very large nor exceedingly cold, because the latent heat of the vapours of tar is small, and consequently a moderately low temperature will be sufficient to condense those vapours to the liquid state. The mixture of gases and vapours maybe compared to an emulsion such as milk, and as the particles of butter may be separated from milk by churning, so the separation of the vapours of tar from the gases can be greatly assisted by the use of exhausters acting in the manner of blowing fans. It is of the utmost importance in condensing the vapours of tar that the molecules of the vapours be kept in continuous motion, and thus made to touch the sides of the condenser. The condenser should not be constructed so that the vapours and gases can flow uninterruptedly in one and the same direction.”[62]

[Footnote 62: B. Wagner.]

An important condition for the safe and quiet distillation of the tar or crude oil when obtained is that it should be free from water. Unless the removal of the water is effectually accomplished, during its distillation, the tar may boil over, and coming into contact with the fire under the still may give rise to an alarming conflagration. The dehydration of the tar is effected in an apparatus constructed for the purpose, consisting of an iron tank placed within a larger tank, a space of about two inches intervening between the two tanks is filled with water, which is heated to, and kept at a temperature of between 60° and 80° C., for 10 hours, by the end of which time the ammoniacal water having separated from the lighter tar is drawn off by a stop-cock placed at the bottom of the tank, whilst the tar is decanted through a valve at the top.

In America the distillation of the natural petroleum oils is carried out in cylindrical stills capable of holding as much as 1600 gallons each. The retorts employed in the distillation of the tar or crude oils obtained from shale and other bituminous compounds are often constructed of large cast-iron flanged pans, each capable of containing from 1-1/2 to 3 tons of the oil, “and forming the body of the retort. The pan is set in brickwork with flues running round the upper portion, and beneath it is a perforated dome of brickwork, through which the flame and hot gas from the furnace pass up round the bottom of the pan before entering the flues by which the upper portion of the pan is heated. To the flange of the pan is fitted a flanged cover having on one side a discharge pipe through which the vapour is passed to the worm of the condenser. In the centre of the cover is a manhole. The oil condensed in the worm is discharged through a pipe into a receiver, and the uncondensable gas escapes through an ascending pipe.”[63]

[Footnote 63: Palen.]

The processes to which the crude oil or tar and the natural petroleum are next submitted differ only in the degree of treatment with certain agents to which these products are subjected when, after similar methods of fractional distillation, they have been isolated from each other. The benzoline and paraffin oils (both for burning and lubricating purposes) separately yielded by the natural oils seldom require purification, or if so in a minor degree only, whilst the same bodies as obtained from the crude shale oil or tar must be submitted to various processes of depuration before they are fit for the market. Thus, the crude petroleum or burning oil derived from tar is characterised by a more or less dark colour and disagreeable smell——properties which are partly due to the presence of carbolic acid and its homologues. By agitating the paraffin oil with a solution of caustic soda these objectionable substances are removed.

The oil, being next separated from the alkali by subsidence, and any remains of the soda being removed from it by washing with water, is next mixed with an aqueous solution of sulphuric acid in the proportion of 5 per cent. of acid of sp. gr. 1·70. The acid removes from the oil certain basic substances derived from the tar, which, like the carbolic acid, give to it a bad odour and a dark colour. In this operation thorough admixture of the acid with the oil is important, and this is generally effected by mixing the two in vessels furnished with puddles. After a time, and when the mixture has separated into two layers, the upper one or the paraffin oil is drawn off from the lower or acid one, and well washed with water; in some instances lime water is used for the washing, in others the water is impregnated with caustic alkali. With some samples of crude paraffin oil the above operations have to be repeated two or three times, and even redistilled before the oil becomes sufficiently pure and colourless for sale. When redistilled, the last portions which come over are often found to yield some solid paraffin in addition to that furnished by the first fractional distillation. The ‘paraffin,’ ‘naphtha,’ ‘petroleum,’ ‘spirit,’ or ‘benzoline’ (by all of which names it is known), which forms the more volatile portion of the tar, and which is the first to pass over from the retort, is subjected to the same treatment as that used for burning oil; as for the denser lubricating oil, which passes over after the burning portion, this being freed from any of the latter, is set aside in a cool place, in order that any solid paraffin it contains may crystallise out, and be separated from it.

The waste carbolate of soda resulting from the treatment of the oil with the caustic alkali, being decomposed by sulphuric acid, the liberated carbolic acid is utilised either as a disinfectant, or for saturating railway sleepers; and sometimes as a source of certain tar colours; or it may be used in the manufacture of gas, the soda which remains in the coke being extracted by lixiviation. The waste sulphuric acid combined with the ammoniacal liquors that always accompany the first stages of the distillation of the tar is made into sulphate of ammonia.

_Prop._ The paraffin oil of commerce is of a very pale amber colour; is bright, perfectly transparent, and remarkably limpid. Its sp. gr. is ·823. Its point of temporary ignition is 150° Fahr., that of permanent ignition being a few degrees higher. Its odour is very slight. Its rate of combustion is slow, as may be inferred from the absence of the lighter oils, as indicated by its high sp. gr. and inflaming point. At the same time its limpidity proves the absence of the heavier oils, and accounts for its rising through a long wick with freedom, and burning without charring the cotton.

=Oil, Petro′leum.= _Syn._ KEROSENE OIL, REFINED PETROLEUM, PARAFFIN OIL. Most of the burning oils now in the market are derived from American petroleum. That obtained from natural petroleum is now manufactured solely in America. The native petroleums vary greatly in properties, and numerous methods of refining are employed by the manufacturers. The Canadian petroleum contains sulphuretted hydrogen, which imparts to it a very disagreeable smell, and is difficult of removal. Some make use of both acids and alkalies, others employ alkalies alone, and steam is applied at various degrees of heat. Some of the oils produced are of excellent quality, but others are inferior, and do not ascend the wick in sufficient quantity to afford a constant light. None of the native petroleums contain carbolic acid and other impurities which exist in the oils distilled from coals and shales; hence their purification is simple and comparatively cheap. “The oil prepared from petroleum is almost colourless; it has a specific gravity of about ·810, and when of good quality only a slight and rather aromatic odour.” (Payen.) See PETROLEUM, and _above_.

=Oil, Shale.= As we have stated, products analogous to those derived from cannel coal are obtained by the destructive distillation of bituminous shales and schists, and lignites or brown coals. On the Continent the production of shale oils has of late years declined considerably, owing to their unsuccessful competition, in point of price, with the American petroleum oils. The oil obtained from bituminous shale or from coal is generally of higher specific gravity than that procured from petroleum; it is deeper in colour, and not so pleasant in smell.

=OILS (Mixed).= _Syn._ COMPOUND OILS; OLEA COMPOSITA, OLEA MIXTA, L. Under these names are commonly included various mixtures of oils and other substances that possess an unctuous appearance. When not otherwise stated, they are prepared by simply agitating the ingredients together, and, after a sufficient time, decanting the clear portion, which, in some cases, is then filtered. A few of them only possess any importance. Some of them are highly esteemed as remedies among the vulgar, and the use of others is confined to veterinary medicine.

The following include the principal mixed oils of the shops, to which the names of a few other compounds, which are frequently called ‘_oils_’ by the ignorant, are added, for the purpose of facilitating a reference to them:——

=Oil of Turpentine, Sulphurated.= _Syn._ OLEUM TEREBINTHINÆ SULPHURATUM. _Prep._ Sulphurated linseed oil, 1 part; oil of turpentine, 3 parts.

=Oil of Turpentine (for acoustic use).= _Syn._ OLEUM TEREBINTHINÆ ACOUSTICUM. (Mr Manle.) Oil of almonds, 4 drams; oil of turpentine, 40 minims.

=Oil, Acou′stic.= _Syn._ EAR OIL; OLEUM ACOUSTICUM, O. TEREBINTHINÆ ACOUSTICUM, L. _Prep._ From oil of turpentine, 1 part; oil of almonds, 6 parts; mix. In atonic deafness, accompanied with induration of the wax. 1 or 2 drops are poured into the ear, or on a piece of cotton wool, which is then gently placed in it.

=Oil, Black.= _Syn._ OLEUM NIGRUM, L. _Prep._ 1. Oil of turpentine, 1 pint; rape oil, 3 pints; oil of vitriol, 1/4 lb.; agitate well together with care; then add of Barbadoes tar, 3 oz.; again agitate well, and in 10 days decant the clear portion. Linseed oil is preferred for the above by many persons.

2. (Percivall.) Sweet oil, 1 pint; oil of turpentine, 2 oz.; mix, add gradually of oil of vitriol; 1-1/4 oz.; again mix, and leave the bottle open until the next day. Detersive, stimulant. Used by farriers for mange, &c.

=Oil, British.= _Syn._ COMMON OIL OF PETRE; OLEUM BRITANNICUM, O. PETRÆ VULGARE, L. _Prep._ From oil of turpentine, 1 quart; Barbadoes tar, 1 lb.; oils of rosemary and origanum, of each 1 oz. Stimulant. Formerly reputed to possess the most astonishing virtues.

=Oil, Camphora′ted.= Liniment of camphor.

=Oil, Car′ron.= Liniment of lime.

=Oil, Chabert’s.= _Syn._ CHABERT’S EMPYREUMATIC OIL; OLEUM CHABERTI, O. CONTRA TÆNIAM CHABERTI, L. Oil of turpentine, 3 parts; Dippel’s animal oil, 1 part; mix, and distil 3 parts. It must be preserved from the air and light. Used in tapeworm.——_Dose_, 1 to 2 teaspoonfuls, in water, night and morning, until 5 or 6 fl. oz., or more, have been taken; a cathartic being given every third day.

=Oil, Exeter.= _Syn._ OLEUM EXCESTRENSE. (Gray.) Green oil, 16 lbs.; euphorbium, mustard seed, castor, pellitory, of each 1 oz.; digest and strain. The original form is more complex. The following is also used:——Rape oil, 1-1/2 pint; green oil, 1/2 pint; oils of wormwood, rosemary, and origanum, of each half a dram.

=Oil, Fur′niture.= _Syn._ MAHOGANY OIL, OIL STAIN. _Prep._ 1. From refined linseed oil, 1 pint; alkanet root, 1/4 oz.; digested together in a warm place until the former is sufficiently coloured, when it is poured off and strained.

2. Pale boiled oil, 1 pint; beeswax, 1/4 lb.; melted together, and coloured as before. Gives a superior polish, which becomes very tough by age.

3. Linseed or boiled oil, 1 pint; Venice turpentine (pure), 6 oz.; as before. The above are used for mahogany and other dark-coloured woods.

4. Linseed oil, 8 oz.; vinegar, 4 oz.; oil of turpentine, mucilage, rectified spirit, of each 1/2 oz.; butter of antimony, 1/4 oz.; hydrochloric acid, 1 oz. Mix.

5. Linseed oil, 16 oz.; black resin, 4 oz.; vinegar, 4 oz.; rectified spirit, 3 oz.; butter of antimony, 1 oz.; spirit of salts, 2 oz.; melt the resin, add the oil, take it off the fire, and stir in the vinegar; let it boil for a few minutes, stirring it; when cool put it into a bottle, and add the other ingredients, shaking all together. The last two are specially used for reviving French polish.

6. (Pale.)——_a._ As the preceding, omitting the alkanet.

_b._ From nut oil, 3/4 pint; beeswax (finest), 3 oz.; melted together.

_c._ To the last add of copal varnish, 3 or 4 oz.

The last three are employed for pale woods. They are all applied by means of a rag, and are ‘polished off’ with a ‘woollen rubber’ or ‘furniture brush.’ A little strong vinegar, or a few drops of hydrochloric acid, are sometimes added. See POLISH.

=Oil, Hair.= See OIL (Perfumed).

=Oil and Hartshorn.= Liniment of ammonia.

=Oil, I′ron.= _Syn._ OLEUM FERRI, O. MARTIS, L. The old name for the liquid formed when perchloride of iron is allowed to deliquesce by free exposure to the air. It is excessively caustic and corrosive.

=Oil, Lime.= See CALCIUM (Chloride).

=Oil, Macas′sar.= See OILS (Perfumed).

=Oil, Mar′row.= _Prep._ From clarified beef marrow, 1 part; oil of almonds, 3 parts; melted together, and strained through muslin. It is usually scented with ambergris, cassia, or mace, and slightly tinged with palm oil or annotta. Used for the hair.

=Oils, Marshall’s.= _Prep._ From linseed oil and rape oil, of each 1 lb.; green oil and oil of turpentine, of each 1/2 lb.; oil of origanum, 1/2 fl. oz.; oil of vitriol, 1/4 oz.; well shaken together.

=Oils, Mixed.= _Syn._ OLEUM MIXTUM COMMUNE, L. _Prep._ From linseed oil and green oil, of each 1 lb.; oil of turpentine, 1/2 lb.; Barbadoes tar and balsam of sulphur, of each 2 oz.; oils of spike and origanum, of each 1 oz. Stimulant and rubefacient. Used by farriers for sprains, &c. See OILS, STAMFORD’S (_below_).

=Oils, Newmarket.= _Prep._ From oils of linseed, turpentine, and St John’s wort, of each 3 lbs.; oil of vitriol, 1-1/2 oz.; well shaken together, and the clear portion decanted in a few days. A favourite remedy for sprains in horses.

=Oils, Nine.= _Syn._ OLD MIXED OILS; OLEUM EX OMNIBUS, L. _Prep._ From train oil, 1 gall.; oil of turpentine, 1 quart; oil of amber and oil of bricks, of each 5 oz.; oil of spike and oil of origanum, of each 2 oz.; Barbadoes tar, 2-1/2 lbs.; oil of vitriol, 2 oz.; camphorated spirit, 1/2 pint, mixed together as the last. A favourite remedy with provincial farriers.

=Oil of Petre.= See OIL, BRITISH (_above_).

=Oil, Phos′phorated.= _Syn._ OLEUM PHOSPHORATUM, L. _Prep._ 1. (Ph. Bor.) Phosphorus (dried and sliced small), 6 gr.; oil of almonds, 1 oz.; mix, place the phial in hot water, agitate for some time, and, when cold, decant the clear oil from the undissolved phosphorus.

2. (Magendie.) Phosphorus (sliced), 1/2 dr.; almond oil, 1 oz.; macerate in the dark, with frequent agitation, for 14 days, then, after repose, decant the clear portion, and aromatise it with a little essence of bergamotte.

3. (B. Ph.) _Prep._ Take of phosphorus and oil of almonds, of each q. s. Heat the oil in a porcelain dish to 300° F., and keep it at this temperature for about 15 minutes, then let it cool and filter it through paper. Put 4 fluid ounces of this oil into a stoppered bottle capable of holding four and a half fluid ounces; then add to it 12 grains of phosphorus. Immerse the bottle in hot water until the oil has acquired the temperature of 180° F., removing the stopper two or three times to allow the escape of expanded air, then shake the oil and phosphorus together, until the latter is entirely dissolved.——_Dose_, 5 to 10 minims.

_Obs._ A fl. oz. of oil dissolves rather less than 5 gr. of pure phosphorus. The large excess ordered in the second formula must be merely for the purpose of increasing the extent of surface acted on. It is, however, with the other precautions given, quite unnecessary. The products of both formulæ have the same strength.——_Dose_, 5 to 10 or 12 drops, in milk, barley water, or gruel, or made into an emulsion; in chronic rheumatism, gout, &c., and as a powerful, diffusible stimulant in various diseases with debility and general prostration of the vital powers, &c. Externally, as a friction. It is chiefly to the presence of phosphorus that cod-liver owes its wonderful remedial power in these affections.

=Oil, Quit′ter.= _Prep._ 1. Red precipitate, 2 dr.; aquafortis, 1 oz.; dissolve, add of olive oil, oil of turpentine, and rectified spirit, of each 2 oz.; and agitate well and frequently for 3 or 4 hours.

2. Ointment of nitrate of mercury (Ph. L.), 1 part; nut oil, 3 parts; melt together, and stir until the mixture is cold. Used by farriers for quitters, &c.

=Oils, Radley’s.= From Barbadoes tar, 1/2 lb.; linseed oil and oil of turpentine, of each 1/4 pint; gently warmed, and shaken together.

=Oil, Shav′ing.= See ESSENCE OF SOAP.

=Oil, Sheldrake’s.= _Prep._ From pale boiled nut oil and copal varnish, equal parts, melted together by the heat of hot water, and, when perfectly mixed, placed aside in a bottle for a week to settle, after which the clear portion is decanted. Used by artists to grind their colours in to brighten them.

=Oil of Spike.= 1. (FARRIER’S). From oil of turpentine, 1 quart; Barbadoes tar, 1-1/2 oz.; alkanet root, 1/2 oz.; digested together for a week. Used as a stimulating liniment by farriers.

2. (PAINTER’S.)——_a._ From rectified oil of turpentine, 3 pints; oil of lavender, 1 pint; mix.

_b._ Oil of turpentine (warm), 5 parts; lavender oil bottoms (genuine), 3 parts; agitate well together, and in a fortnight decant the clear away. Used by artists and enamellers.

=Oils, Stamford’s.= _Syn._ LORD STAMFORD’S MIXED OILS. _Prep._ Dissolve camphor, 1 oz., in rectified spirit of wine, 1/4 pint; add oil of origanum, 2 oz.; oil of turpentine, 1/2 pint; green elder oil, 2 lbs.; and agitate until mixed. The rectified spirit is now generally omitted, the camphor being dissolved in the green oil by aid of heat before adding the other ingredients. Stimulant. Used by farriers.

=Oil, Sul′phurated.= _Syn._ BALSAM OF SULPHUR; OLEUM SULPHURATUM, BALSAMUM SULPHURIS, L. _Prep._ 1. (Ph. L. 1746.) Flowers of sulphur, 1 part; olive oil, 4 parts; boil together in a vessel lightly covered, until they assume the consistence of a thick balsam.

2. (Ph. L. 1824.) Olive oil, 16 fl. oz.; heat it in a sand bath, and gradually add of washed sulphur, 2 oz.; stirring until they combine.

_Prop., &c._ Balsam of sulphur is a dark, reddish-brown, viscid fluid, having an extremely disagreeable and penetrating odour, and a strong, nauseous taste. The local action of balsam of sulphur is that of an acrid and irritant; its remote effects those of a stimulant, expectorant, and diaphoretic. Externally, it is occasionally used as an application to foul ulcers; and was formerly commonly employed internally in chronic pulmonary affections, in doses of 20 to 50 drops. It is now seldom given internally except in veterinary practice.

=Oils, Three.= _Syn._ OLEUM DE TRIBUS (Van Mons), L. Oils of brick, lavender, and turpentine, equal parts. As a stimulant liniment.

=Oil of Vit′riol.= Sulphuric acid.

=Oils, Ward’s.= _Syn._ WARD’S WHITE OILS. From powdered camphor, rape oil, oil of turpentine, rectified spirit, and liquor of potassa, equal parts, agitated together for some time, and again before use. Beef brine was formerly used instead of liquor of potassa.

=Oil, Watchmaker’s.= Prepared by placing a clean strip or coil of lead in a small white-glass bottle filled with pure almond or olive oil, and exposing it to the sun’s rays at a window for some time till a curdy matter ceases to be deposited, and the oil has become quite limpid and colourless. Used for fine work; does not become thick by age.

=Oil, Wedell’s.= _Syn._ BEZOAR OIL; OLEUM BEZOARDICUM, L. From nut oil, 1/4 pint; camphor, 1/2 oz.; dissolve by a gentle heat, and, when cold, add of essence of bergamot, 1 dr., and let it stand over a little alkanet root until sufficiently coloured.