Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/929

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have fucceeded amifs in trying the experiment from their neglect of certain circumftances which appeared trifling to them, have cenfured both authors as relating untruths. But Mr. Geoffrey, by repeated experiments, at length found the truth of the affertion, and became able at any time to en- flame fuch mixtures, but found that fpirit of nitre was the acid which fucceeded beft ; and that of all oils thofe of the foreign exotic vegetables, which are thick and heavy, were moft readily inflamed by it. Mr. Tournefort produced ac- tual flame, and that of a ftrong red colour, by mixing fpirit of nitre and oil of faflafras in equal quantities ; but he try'd without fuccefs the fame experiment with many of our Euro- pean oils, and indeed with the foreign oil of cloves. After this, however, Mr. Homberg fucceeded in the attempt with oil of cloves, and with all the aromatic oils of the Indian ve- getables. Mem. Acad. Par. 1702.

After this, Mr. Rouviere found the means of fucceeding in it with the fpirit of nitre and the feet id oil of guaiacum, in which experiment the fpirit not only fet lire to the oil, but made a fort of volcano in it, raiting up a mafs of fpungy matter to the height of two inches above the furface of the vellel, in which it was made. All thefe experiments how- ever do not prove the truth of Borrichius's experiment in the literal words, fince none of thefe gentlemen were ever able to produce fire with oil of turpentine, 'with the aflif- tance of any acid whatever ; there required for this an aqua fortis deflegmated in the highell degree. Mem. Acad. Par. 1726.

Mr. Geoffroy at length prepared a fpirit of nitre fo perfectly deflegmated, that it would always give flame with oil of fai- fafras or oil of cloves; this he prepared by mixing four parts of clay with one of nitre. The clay and the nitre for this procefs mull be both perfectly dried, and mull be mixed while yet hot and put into the retort ; after this, the fpirit which comes full over muft be feparated, as it yet contains fome phlegm i the fucceeding fpirit muft be kept alone, for this purpofe. This is too itrong for the common ufes in the metallic folutions, but it always fucceeds in giving fire with the oils. Another acid which the fame author has de- fcribed as capable of producing the fame effect, is an aqua fortis made too ftrong for the fblution of metals : This is pre- pared by mixing equal quantities of vitriol calcined to a red- nefs, while it is yet hot with an equal quantity of nitre dried and reduced to powder.

As this operation however is attended with its difficulties, the fumes ariiing on the mixture of the two falts greatly in- commoding the artift, the fame author defcribes a third li- quor, made by adding powdered nitre to concentrated oil of vitriol, and giving a considerable heat to the mixture. This without diftillation yields a fort of aqua fortis, which, tho' inferior in ftrength to the former, yet will produce flame on mixing with the oil of guaiacum. Tho' this however will <lo without diftillation, yet a diftilled fpirit prepared from three parts of dried and powdered falt-petre mixed with one part of oil of vitriol, with the help of a reverheratory fire is greatly fuperior to it. This is a liquor fo fuming, that it is icarce poflible to keep it even in glaffes ever fo well flopped ; and it very readily takes fire with all the aromatic oils of the Eaft-Indian plants ; but even this will not produce the fame effect with oil of turpentine.

The firft experiment which fucceeded with Mr. Geoffroy in this particular, was this : He mixed in a fmall retort an ounce of oil of vitriol with an ounce of fuming fpirit of nitre, and pouring on this mixture two ounces of oil of tur- pentine, a thick fmoke and a large quantity of flame were immediately produced, and this continued a long time till all the liquid matter of the mixture was confumed; and there remained nothing but a fmall quantity of a black light mat- ter, refembling a coal.

This fuccefs and the fimilitude of this mixture of acids, with the liquor diftilled by the fame author from vitriol and nitre, gave the hint for the following compound acid, which, more conftantly and happily than any other, produces this won- derful effect.

Take two pounds of nitre dried and powdered, mix it with one pound of concentrated oil of vitriol, or of common oil of vitriol of a fufficient ftrength; diftil this mixture in a retort with a reverberatory fire, and the liquor railed from it will be an aqua fortis capable of giving fire and flame with oil of turpentine, without any farther afliftance. Mr. Hoffman has alfb given the procefs for another acid fpirit, which produces the fame effect ; and which, though founded on the fame bafts with the former, differs in fome particulars. This is made by mixing in a retort equal quan- tities of purified nitre and oil of vitriol, and diftilling the whole in a mild fand heat. Mr, Geoffroy tried this and found it anfwer in every particular, and give fire with oil of turpentine even more readily than the inventor had declared; for he orders the ftiaking of the veffel in which they are mixed, and then ftanding fome time ; whereas Mr. Geoffroy on carefully repeating every article of his procefs, found there was no occaiion for fhaking the veffel, nor that any time was required ; but that the flame appeared inftantane- oufly on making the mixture, and that in a more violent man- Suppl. Vol. I.

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ner than could have been expected from fuch an operation- In order to the fuccefs of this furprifrng operation, however no more is neceflary than that the acids of nitre and vi- triol fhould be mixed ; the manner of doing it is of no confequence. But without the trouble of making either of thefe fpirits, if common fpirit of nitre well dephlcgmat- ed be mixed with a fufficient quantity of oil of vttriol, it will give fire* and that very violently with oil of tur- pentine, or any other of the European oils of vegetables. The beft vellel to perform the experiment in, is that fort of glafs uicd for preferring fruits in brandy, which is about a foot high, and three inches in diameter. Mem. Acad. Par. 1726.

Mr. Geoffroy fucceeded in this manner in giving flame with oil of juniper, mint, fennel, the vulnerary herbs, and eflence of lemons, notwithflanding that they are much thinner fluids than the oils of the aromatic plants of the Indies. And this fcems indeed a better method than the relyin^ on any fpirit of nitre by a particular diftillation, fince in that way there are a great many accidents which may prevent the fuccefs of the experiments, and in this all is familiar and eafy.

As all thefe experiments are attended with fome cxpence, Mr. Geoffroy has endeavoured to reduce them to the cheap- en: and eafieft method that may be. Mr. Hoffman fays, there mull be at leaft an ounce of the acid, and an ounce of the oil, to produce the effect ; but Mr. Geoffrey has found it fucceed very well with a dram of fpirit of nitre, a dram of oil of vitriol, and three drams of oil of turpentine. The heavy oriental oils fucceed with a fmaller portion of acid ; and it feems a general rule, that the lighter the oil is, the larger portion of the acid is required, Petroleum and naphtha, with the other inflammable mineral oils, might be fuppofed very fit for thefe experiments ; but none of them fucceed on the trial.

It is not only the oils of our European plants, as well as the Indian ones, that are to be let on fire by mixture with thefe acids ; but the very natural balfams perform the operation in the fame manner, and afford the fame furprifmo- phe- nomenon.

An ounce of common Venice turpentine will be immediately fet on fire, by pouring on it a mixture of an ounce of fpirit of nitre, and half an ounce of well rectified oil of vitriol. This is a very fine experiment, for the flame continues lon- ger than that from any of the oils, and is rendered a more pleating fpectacle by a great number of explofions, which fucceed one another at different diftances of time. Balfam of capivi and balm of Gilead, fucceed in the fame manner in the fame dofes ; and the balm of Gilead yields its flame with a very remarkable explofion, and probably ajl the natural balfams will produce the fame effect ; but in or- der to fucceed in the experiment, it is neceffary to have them perfectly genuine and unadulterated. The fmoke and vapours that attend the flame in thefe expe- riments always dift'ufe a very ftrong fmell of the fubftance that is employed ; and the petroleum, tho' it will not yield a flame in this fort of mixture, yet diftufes a very remark- able fmell of ambergreafe ; and the leafl touch of the matter while fuming will give a fmell of that perfume, which will laft a very long time. Mem. Acad. Par. 1726.

INFLAMMATION {Cyd.)~ A late author is of opinion, that the ophthalmia, angina, phrenitis, peripneumonia, pleuritis, hepatitis, nephritis, and rheumatifmus, have all the fame characteriftic, and differ in nothing but the part affected ; fo that if one has a right knowledge of an /«- flammat'ion on an external part,- its progrefs and proper re- medies, and at the fame time is throughly acquainted with anatomy and the animal ceconomy, he cannot be at a lofs to diftinguifh and treat any of the difeafes belonging to this clafs. Medic. Eff". Edinb. Vol. 1. p. 265.

Difperfion of Inflammations. See the article Disper- sion.

INFLEX-Lw/", hiflexum Folium, among botanifts. See the article Leaf.

INFLUENT {Cych) — Influent Fever is fometimes ufed for a nervous fever. In this the warm regimen is thought ufe- ful by fome, as low cooling drinks are in the effluent or in flammatory fever.

INFORMER, Informator, in law, a perfon that informs a- gainft, or profecutes in any of the king's courts thofe that offend againft any law or penal ftatute. Blount, Cowel.

INFRASPINATUS (£.>/.)— This is a triangular flefhy and pretty broad mufcle, in fome meafure penniform, filling the whole infroj'plnol cavity, or fbffa of the fcapula. It is fixed in the pofterior half of the infrafpbial cavity, or fofla, and to the correfponding part of the bafis of the fcapula. From thence arife a great number of fhort flefhy fibres, which run more or lefs obliquely, and end in a middle ten- dinous plane, which terminates a little below the broadefl part of the fp'me of the fcapula, under the root of the acro- mium. The flefhy fibres then leaving the bone, unite in one flefhy mafs, which paffing under the acromium over the articulation of the head of the os humeri, and adhering to the capfular ligament, terminates there in a broad flat tendon, 14 F which