CAM
CAM
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camphor be mixed with water and put into thedecanter-part of the apparatus, plate iii. fig. 47.then let carbonic acid be thrown in from theretort, and combined with the water by agi-tation, as long as any continues to be taken upa highly carbonated water will thus be produced,in which a fufficient quantity of camphor isdiffolved to make it both tafte and fmell verypowerfully of this fubftance.
Vinegar and muriatic acid will each of themby digeftion take up a fmall portion of camphor.The muriatic and fluoric acids, when in theftate of gas, diflolve a confiderable proportionof camphor, but depofit nearly the whole bythe contact of water. Concentrated fulphuricacid difiolves camphor largely even in the cold,but by the affi fiance of a moderate heat it takesup fo much as to form a thick homogeneousmafs of a brown or black colour and a fulphu-reous odour, which when warm is fluid, butcoagulates by a moderate heat, and by evapo-ration is brought to a refinous confiftence. Thiscompound is foluble in alcohol, but is decom-pofed by water: the camphor being difengagedwith little or no alteration, and the mixture nowno longer exhaling a fulphureous but a cam-phoric odour. The aftion of oxygen on cam-phorized fulphuric acid is remarkable. If onepart of camphor is difl'olved in eight parts offulphuric add, and this liquor is poured in aretort upon four parts of black oxyd of man-ganel'e and as much water, the refult of a flow.diftillation of thefe materials will be acetousacid mixed with a very fmall portion of un-clccompofed camphor.
Nitric acid when fomewliat concentrated dif-folves camphor in confiderable quantity at the■ufual temperature. The folution is of a verydilute yellow colour, and feparates by Handinginto two diftindt liquids : the lower confilts of amixture of nitric and camphoric acids-, theupper fluid is of the confiftence of oil, and iscalled acid oil of camphor ; it is a combination ofcamphor and nitric acid. This oil is foluble inalcohol, but is decompofable with precipitationoi the camphor by water or alkalies: the additionof oxymuriatic acid gas converts it at firft to arofe colour, and afterwards to a full yellow, andin all probability acidifies the camphor.
The converfion of camphor into a peculiaracid by repeated diftillation with nitric acid wasfirft obferved by Kofegarten, and was after-wards more fully elucidated by La Grange.
The procefs of Kofegarten is the following. kPut one part of camphor into a retort with 12
parts of ftrong nitric acid, and diftil it flowly todrynefs a large quantity of carbonic acid andnitrous gas is difengaged, and the acid in thereceiver is covered with a thin ftratum of acidoil of camphor: a fmall portion of the camphorfublimes into the upper part of the retort, andthe mafs at the bottom of the veflel is camphorapproaching to the ftate of a vegetable oxyd.It has no longer the peculiar odour of the origi-nal fubftance, and when laid on a hot coal itevaporates with a fomewhat refinous odour,but without undergoing combuftion : it is folu-ble in alcohol but not in water. This oxygenatedcamphor by being diftilled twice to drynefs with,ten parts of nitric acid at each procefs, is con-verted to a white pulverulent fait, foluble in hotwater, and which has obtained the name ofCamphoric acid.
The method of La Grange differs chiefly inrequiring a fmaller quantity of nitric acid. 1He takes one part of camphor and four of nitricacid, and diftils the mixture by a very gentleheat: the acid that pafles over into the receiver,being mixed with four parts more of frefh acid,is returned upon the matter in the retort andagain diftilled. This is repeated five feveraltimes with 2o parts of nitric acid in the whole,and the operation is known to be finilhed whenthe liquor in the retort cryftallizes on cooling.The produce of camphoric acid by either ofthe methods does not much exceed one half ofthe camphor made ufe of.
Camphoric acid when cryftallized haftily ap-pears as a mafs of white filvery filaments, butby flow cooling aflumes the form of parallelipi-pedal or rhomboidal plates, which efflorefee onexpofure to the air. To the tafte it is flightlyfour and bitterifh : it reddens fyrup of violetsand tincture of litmus. It diflolves eafily inalcohol and in hot water, but requires 2po partsof this fluid at the ufual temperature for itsfolution. When heated it gives out a thickaromatic fmoak, and is entirely diiflpated: inclofe vefiels it fublimes unaltered if the heat isnot too great. The alcoholic folution of thisacid is not decompofed by water, a circumftancethat diftinguifhes it from benzoic acid, to whichit bears a confiderable refemblance. It is folu-ble in the exprefled and efl'ential oils and themineral acids, and forms a precipitate with themuriat and fulphat of iron.
Camphoric acid unites with the falifiable balesforming a genus of falts, the Camphorats.Of thefe very little is known. The neutral andearthy camphorxts, which are the only ones
1 Manuel, ii. p. 357-