Iodine, and the Essential Oil of Cinnamon. 115 



Starch would appear to decompose this substance, for with 

 even its alcoholic or iEthereal solution it forms the well-known 

 blue compound. When agitated with water and zinc or 

 iron filings, an iodide of these metals is produced, and the 

 oil is set free. With mercury the result is the same, and in 

 each instance for water alcohol or aether may be substituted. 

 Potash also at once developes the oil, forming, as in the case 

 of free iodine, iodide of potassium, and iodate of potash. 



From these facts it seems legitimate to infer that it is the 

 oil, and not any modification of it corresponding to the ben- 

 zoyle of chemists, which is associated with the iodine and 

 iodide of potassium, and that they are all held together by an 

 extremely feeble affinity, in as much as not only is the iodide 

 of potassium separated by water, as has been stated, but 

 the iodine is affected by a solution of potash just as if it 

 were free. To test the truth of this opinion, a little of the 

 compound was decomposed in a small glass retort by the ex- 

 act equivalent of a very dilute caustic alkali, and, a receiver 

 being applied, about half an ounce of a liquid having the 

 appearance and obvious properties of cinnamon water was 

 drawn off by distillation. From it, however, I could not, 

 though every precaution was employed, procure a particle of 

 the original crystalline compound. The properties, indeed, 

 of the distilled liquid were not, upon an accurate examination, 

 identical with those of cinnamon water. Its odour, for ex- 

 ample, was slightly different, and it reddened litmus, a cir- 

 cumstance from which it may be inferred to contain cinnamic 

 acid. It is therefore not unlikely that the oil may have ab- 

 sorbed oxygen or have been otherwise altered during the 

 distillation ; and as a confirmation of this opinion I may men- 

 tion that the oil of cassia which is found in the market, is 

 chiefly cinnamic acid, and that a cinnamon water prepared 

 from it by a process directed in some of the pharmacopoeiae 

 yields but a very minute proportion of the substance which 

 is the subject of the present paper. 



With a view to the analysis of this compound the first 

 point to determine was the proportion of iodide of potassium 

 which it included. To accomplish this a known weight of it 

 was heated in a small porcelain capsule, by which iodine and 

 oil of cinnamon wei'e expelled in the vaporous state, and there 

 remained amixtureof iodide of potassium with a little carbon 

 resulting from the decomposition of a portion of the oil. The 

 iodide of potassium was separated from the carbon by solu- 

 tion in water, and the use of a single filter which had been 

 previously deprived of all soluble matter by the action first 

 of a dilute acid, and subsequently of distilled water. The 



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