Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/144

 O I L

O I L

6ESTUM Veneris^ a name given by fume anatomical authors to the clitoris.

OETHODES uktts.) a term ufed by the Creek writers for fuch ulcers as bad tumid, and callous lips ; and as fuch ulcers are ufually very difficult to heal, the word became afterwards ap- propriated to all forts of ulcers difficult to cure.

OYY -fet-ffaff, in furveying, a rod, or (raff", of any con- venient length ; for inftance, of 10 links of the chain. This ftaff is divided into 10 equal parts. Its ufe is for the ready meafuring the diftances from the ftation line of things proper to be reprefented in a plan. See Chain.

OFF-ward, in the fca language, the fame with contrary to the fliore ; thus they fay, the Jin p heels off-iv.trd, when, being a- ground, Hie heels towards the water fide ; the jhip lies with her ftem to the off- war d, and head to the fare-ward, when her ftern is towards the fea, and head to the fhore.

OFFA alba-, {Cycl.) in chemiftry, a concretion produced by a due mixture of fpirit of urine, or fpirit of fal armoniac with the fpirit of wine. Some call it the offa alba of Paracelfus % others of Van Helmont, whence it is fometimes called offa Helmonti- ana \ but Van Helmont was not the inventor of it, but Raim, Lully, fays b Boerhaave.

The manner of making the offa alba is defcribed in this laft author c, who obferves it to be difficult, as it requires both liquors to be perfect, and fome nice circumftances to be ob- ferved. — [ a Boyle's Works, abridg. Vol. j. p. 37. b Boerh. Chem. V0I.2. proc. 122. c Id. ibid.]

Van Helmont s endeavours to account for the formation of the ftone in the bladder, from this experiment; but, as Boer- haave D obferves, the offa alba has nothing in common with the ftone. — [ 3 Boyk^Xoz. cit. b Ibid.] Bocrhaave recommends this mixture as a good deobftruent, taken in Canary fafting. Ibid.

OFFENCE, d liStwn, in law, an act committed againft the law, or omitted where the law requires it. JVeJl, Symbol. Offences are diftinguifhed into two kinds, viz. fuch as are capi- tal, and fuch as are not. Capital offences are thofe for which the offender is to Iofe his life. Thofe not capital, where the offender may forfeit his land;, and goods ; be fined, or fuffer corporal punifhment, or both, but not lofe his life. Hale, P. C. 2. 126, 134. Under capital offences are comprehended high treafon, petit treafon, and felony : qnd offences not capi- tal include the remaining part of the pleas of the crown, and come under the title of mifdemcanours.

Some offences are punifhable by the common law, but moft of them by ftatutes.

OtTICIARllS nmfaciendis, vet amove?idis, a writ directed to the magiftrates of a corporation, requiring them not to make fuch a man an officer, or to put one out of the office he hath, until enquiry is made of his manners, &c. Reg. Orig. 126. Blount, Cowel.

OFFION, a name ufed by fome of the medical writers for opium.

OIL (Cycl.) — The ufe of oil in flopping the violent ebullition of various fubftances, may be very great in many occafions of life. It is well known that if a mixture of fugar, honey, or the like, be boiling on the fire, and in danger of rifing over the fides of the vefiel, the pouring in a little oil immediately makes it fubfide. In many cafes the marking a circle round the infide of a veffel, in which' a liquor of this kind is to be boiled, with a piece of hard foap, mail, like a magic ring, confine the ebullition to that height, and not fuffer it to ftir any Farther. This is wholly owing to the oil, or fat contained in the foap : but there is, befide thefc, another very important ufe of 0//, on alikeoccafion, which is the pouring a little of it on any metallic folution, while making ; this reftrains the afcent of the noxious vapours ; preferves the operator from danger; and, at the fame time, by keeping down the evaporating mat- ter, gives redoubled ftrength to the menftruum.

jfnimal 0\t, oleum animate, in medicine, the name of an effen- tial oil diftilled by a retort from blood, and recommended as a powerful remedy in epilepfies, the gout, and other obftinate difeafes.

It was originally ufed in Germany in thefe intentions, and has become of late much ufed in England, but mould not be given too freely as an internal. As an external, it may probably be of good fcrvice in removing fixed pains, removing hard tumors, &c. for it is extremely penetrating. Shaw's Lectures, p. 147-

Oil f camphor, a name given by the chcmifts to a folution of camphor in fpirit of nitre. It is ufed to exfoliate carious bones, and on other the like occafions It is obfervable, that cam- phor, which is folublc in this acid, in the proportion of one half its quantity, is not at all foluble in fpirit of vitriol, fpirit of alum, or diftilled vinegar ; and that it is the only known vege table rcfin that is foluble in this menftruum. See Camphor Comical 'Oils, a name given by fome to the effential oils of plants, and other fubftances feparated in dilf illation, and fwim- ing on the furface of the water, where the alembic is em- ployed. They are diftinguifhed by this title from the ex- preffed oils, fuch as thofe of almonds, linfecd, olives, and the like, which are made by fo fimplc a procefs as mere fqueezin?. See effential Oils, infra. To procure this chemical principle pure and unmixed from the

matter diftilled from a vegetable body, the unctuous matter obtained from the procefs, may be warned from its adhering falts, and groffer earth, in warm water, barely by making them in a glafs together, then feparating the oil from the water by means of the common feparating glafs ; in which, if the oil be fpecifically heavier than the water, it finks to the bottom, and may be fuffered to run out firft, by means of the pipe of that glafs which has its infertion at the bottom ; if fpecifically lighter than the water, it maybe kept behind, as it floats on the top of the water, while all that is poured off, and has car- ried the grofs feculent parts with it. Shaw's Lectures, ^ p. 150.

Co?ine£iing Oil, in chemiftry, a term ufed by Bnerhaave, and his followers, to exprefs a certain oil, found in all vegetable fub- ftances, but wholly differing from, and independent of, their effential oil. This is not pufleffed of any of their virtues, or qualities, but feems the fame in all plants, and is the means of their confiftence and folidity, giving tenacity to their earth, which, without it, falls to dull, and the plant cxifts no more,

This oil is not feparable by boiling water, as the effential 01/ is, but only by fire : when a plant has been boiled, and diftilled, its effential oil, fait, &c. are all carried off, and what remains is only the earth connected by this oil. This being cxpofed to the fire, the oil difcovers itfelf in a thick, black, ftinking fmoak, and finally, taking fire, it burns away, and leaves only the earth which was the bafis of the plant, retaining its form, indeed, if the procefs have been carefully made, but falling into a fhapelefs powder only on being roughly breathed upon.

This great author, therefore, eftablifhes it as a rule, that there are three forts of oils in plants. 1. An oily froth. 2. The effential oil, diffolved in decoction. And, 3. This connecting, or anjolidating oil, feparable only by a naked fire. Beer. Chem. Part z. p. 20.

Effential On.. There is found in every plant analyfed by di- ftillation, an effential oil - 3 but this is very different from the fame plant, both in its quantity and in its qualities, as it is managed in the operation.

If a plant be thrown into a retort, and diftilled with a vio- lent fire, it is known to yield Iefs oil, than if the nre were more moderate : if the plant be fermented, efpecially if it be of the aromatic kind, it always yields much more oil after this operation, than it does without it. It is plain from hence, that there are methods of obtaining more oil from the fame plant, than would be yielded by it in the common way ; and it is as certain, that according to all the methods in common ufe, there is ever left a large quantity of the oil behind ; and therefore, that a way may poffibly be invented of drawing yet more from the fame plant than is yet known to be done. We all know, that when the refiduum in the retort, after the diftillation of the plant, is burnt in the open air, it lofes half, or of- ten three fourths of its weight, and the matter evaporated in this burning to caufe this great diminution can be onlv the remainder of the oil of the plant, which would not be fe- parated from its earth in a clofe veffel.

It may be obferved alfo, that the oil of a plant, in the di- ftillation by the retort, never comes over till toward the end of the procefs, and drops from the neck of the vefiel at the fame time with the acid fpirit of the plant, and while the urinous volatile fait is alfo rifing; fo that the three princi- ples are, in a manner, all feparated from the plant toge-

and but a fmall quantity of urinous fait, it is alfo conftant- ly obferved, that there is a larger quantity of oil, and that this oil is more fluid, and that the caput mortuum diminifhes lefs in burning. This particular is remarkably obfervable in the analyfes of mallows, prunella, melilot, and fouthernwood. On the contrary, fuch plants as yield but a fmall quantity of acid fpirit, or volatile fait, always iifford but little oil, and that a/is always thick, and the caput mortuum of thefe plants diminifhes greatly in burning ; that is, a great quantity of the oil was entangled in the earthy matter, and could not get Joofe, otherwife than by burning the plant in the open air. Inffances of this fort are found in the analyfes of the caltha palujlris, Sec.
 * ther : when there is a large portion of acidity in the plant,

Hence it appears, that the acid and volatile fait in plants are greatly inftrumental to the difengaging their oil, and giving it feparate in diftillation. Hence when a plant does not contain acid enough in itfelf to difengage its «7j it ap- pears no ill method to try to affiil the feparation by the addition of another acid of the vegetable kind. To try this, Mr. Homberg firft diftilled a certain quantity of fennel-feed in the common way, and afterwards diftilled the fame quantity of the fame feed, in the fame manner, except that he added for every pound of the feed four ounces of fpirit of fait to the water in which it was put for diftillation This laft diftillation yielded one third more oil than the firft Eoth the oils were equally clear, and ftrong- (tented of the feeds, but the laft femed to fmcll lefs of the fire than that obtained by the fimple diftillation in the common way. There is no doubt but that the fpi- rit