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being in an inverfe ratio to the temperature.If oil of lavender is diftilled from a water bathin an alembic, at a temperature inferior to boilingwater, till one-third is come over, the remain-ing two-thirds will depofit flakes of camphorwhile cooling, thefe being removed, and the dif-tillation being repeated, a frefh depofition willtake place in the refidue, and a third diftillationwill yield all the remaining camphor exceptabout 4 per cent. This however being a muchmore rapid procefs than fpontaneous evapora-tion, the total produce of camphor from thethree diftillations does not amount to more than2o per cent, the reft being held in folution bythe oil in the receiver. If the balneum maria ismade to boil, the produce of camphor will beconfiderably diminifhed, and part will fublimeinto the capital of the alembic. The camphorfrom oil of lavender by either erf thefe methodsis not abfolutely pure, for when fublimed per fe,at a gentle temperature, it leaves behind a fmallportion of brownifh refin {till mixed with a littlecamphor. The mofl economical way of refiningthis camphor is to mix it with half its weight ofchalk, or lime, or wafhed wood afhes, and fub-lime it, by which operation it lofes of itsweight. The produce of refined camphor there-fore by fpontaneous evaporation of oil of laven-der amounts to about 24 per cent, and by dif-tillation is equal to 19 per cent.: this latter me-thod however is by far the moft economical,notwithftanding the additional expence of fueland apparatus, as it faves both time, and theoil, which would otherwife be entirely loft.

The production of camphor by the action ofmuriatic acid on oil of turpentine is a difeoveryof very late date, and though it ftill requiresfome further elucidations, the leading facts ap-pear fufBciently confirmed to juftify their in-sertion in this place.* M. Kind, while preparingthe arthritic liquor of Pott by palling muriaticacid gas through oil of turpentine, obferved themixture to depofit by cooling, a large quantityof cryftals pofleffed in almoft every refpect ofthe .characters of camphor. The experimentwas repeated by TrommfdorfF with the fame re-fult; and the fociety of pharmacy at Paris beinginformed of thefe faCts, nominated three of theirmembers to repeat the inveftigation, and makea report on the fubjeCt. From thefe fources thefollowing information is derived.

A fmall quantity of camphor may be obtainedfrom oil of turpentine Amply by diftillation, pro-vided this procefs is carried on fufficiently:(!owly. Eight ounces of this fluid were diftilled

in a glafs alembic at about the temperature of124° Fah.; four ounces of very highly rectifiedefiential oil paffed into the recipient, and thecapital was found lined with fmall cryftals ofreal camphor.

This fubftance is however procured in muchlarger proportions by the afliftance of muriaticacid. Four pounds of oil of turpentine wereput into a Woulfe’s apparatus, and the retortbeing charged with the fame weight of decre-pitated muriat of foda, and half as much fulphu-ric acid, the whole of the muriatic acid gas thatcould be obtained by a moderate heat fromthefe materials was tranfmitted into the oil ofturpentine, and wholly abforbed by it. In con-fequence of this the oil became exceedingly hot,and acquired firft a fight lemon colour, andtowards the end of the procefs a clear tranfparentbrown, a fmall quantity of a thick oily fluid be-ing gradually difengaged and finking to the bot-tom. The liquor being allowed to cool fortwenty-four hours was found concreted into afoft cryftalline mafs, from which, when laid Oila Hoping furface the brown liquor drained away.Being then wrapped in filtering paper and fub-jected to moderate preffure, twenty-four ouncesof a perfectly white cryftalline matter were leftbehind of a peculiar odour, in fome degree par-ticipating both of oil of turpentine and muriaticacid. The liquor which had drained from thecryftals was placed in a cool cellar, and in thefpace of a few days was found to have depofitedfour ounces more of cryftals, and two ouncesadditional were obtained by expofing it to apowerful freezing mixture. Thus four poundsof oil of turpentine yielded thirty ounces ofcryftals ; or not far ftiort of half its weight.

The cryftals of rough camphor thus obtainedacquired a dazzling white colour by {implywafhing with water, but ftill retained a terebin-thinate odour ; the walhings were acidulous tothe tafte, having taken up a little muriatic acid,and were highly aromatic. Another portionof cryftals being wafhed with a weak folution ofpearlafh was found to refemble common cam-phor in its odour, that of turpentine havingnearly difappeared. It was thought that fub-limation would be ftill more effectual thanwafiling in purifying this camphor, accordinglytwo portions of it were mixed, the one with anequal weight of charcoal, the other with quick-lime, and were heated in glafs alembics: the ca-pitals foon became covered with radiating needle-Ihaped cryftals of a brilliant white colour, en-tirely free from the terebintltinate odour, and

• An, de Chinj.. li. p. 27?.

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