METHOD OP RESTORING RANCID ESSENTIAL OILS,. ^ 



tated it from its folution in alcohol by water, according to my Oil was fe- 

 method, and four ounces and a half of oil were feparated as Sot by Sdll'^ 

 tranfparent and colourlefs as water. ing water. 



I then poured the refiduum of the ftill, together with the Second diftllla- 

 fpirit and the water of precipitation, after having feparated the p°o"(iuas!! 

 oil, into an apparatus over a naked fire, and diftilled a fecond 

 time. I had the fatisfa6lion to find a fpirit rife, the water of 

 which, that came over at the fame time, depofited an oil as 

 perfed as before, I repeated this cohobation by pouring the Cohobatlon and 

 mixture of fpirits and water on the remaining oil through the ^^' ations, 

 neck of the alembic until I had colleded in all twelve ounces 

 and a half of oil as fragrant and free from rancidity as the gave a pure oil. 

 freftieft and befl oil of peppermint. 



I reaified the fpirits and judged by fome trials that it might Some oil In the 

 contain rather more than one ounce and a half of oil. 



What remained in the ftill was a thick adhefive matter ^^ ^^[{^''J'ft-i,"^*"^' 

 the nature of turpentine. I boiled it with water, and obtained 

 ten gros (drams) of a fort of dry turpentine fimilar to refin. 



It is difficult to afcertain in what manner the addition of Theoretical fpc- 

 alcohol, or ether, contributes to the reftoration, and in fome 

 meafure the regeneration of fo large a quantity of eflential oil, 

 which had loft the greateft part of its peculiar odour. 



Formerly it would have been faid, that the fpiritus re61or, 

 with which the alcohol of peppermint was impregnated, had 

 produced this eflfed ; but now when we know that the fmell of 

 an eflential oil does not depend on a peculiar principle, but on 

 a conftitution proper to the oily compound, we cannot admit 

 that the oil of the alcohol had rendered any particle of the dif- 

 aromatized oil odorant; but we muft fuppofe that the ether or 

 the alcohol are in their decompofition identified with the fub- 

 ftance of the oil. 



In facl, the alcohol, and more efpecially the ether, contains 

 as a conftituent part hidrogen, which is the bafe of almoft all 

 the odours. Alcohol, ether, and the efTential oils, are equally 

 difpofed to undergo an alteration in the relative proportion of 

 their principles. There is confequently no obftacle to our ad- 

 mitting this concurrence of chemical operation for the refto- 

 ration which I have obtained of the oil of mint. 



Another circumftance tends to fupport this explanation. I 

 at firft attributed the oil which I obtained in the fecond ope- 

 ration to the difference of temperature of the bath, and of the 



naked 



