Professor Apjohn on a new Compound. 163 



a single filter, which, when sufficiently drained, is enveloped in several folds of 

 blotting paper, and transferred to a chalk-stone, where by the absorbent powers 

 of the latter, and the occurrence of spontaneous evaporation, the product is ren- 

 dered perfectly dry and pure. With the quantities stated above sixty grains of 

 the compound are obtained. A temperature at, or very close to 32° is necessary 

 to the success of this process. At 40° the brown powder already noticed is alone 

 produced, and in much diminished quantity. This broviTi sediment, however, 

 is identical with the crystalline product, for it may be converted into crystals 

 simply by reduction of its temperature ; and I have even found it to undergo the 

 same change when collected on a single filter, and set to dry on a bibulous stone 

 at the temperature of 45°. 



The crystals are capillary quadrilateral prisms, without pyramidal termina- 

 tions. They are of a beautiful brown or bronze colour, and have a strong 

 metallic lustre. Their taste is extremely hot and pungent, resembling closely 

 that of oil of cassia, but partaking also of that of iodine. In alcohol and ether 

 they are readily dissolved, and from these solvents they are again deposited with 

 their original appearance upon the occurrence of spontaneous evaporation. They 

 are decomposed by water, which extracts from them iodide of potassium, and 

 causes the separation of oily drops of a dark colour, which are either a mecha- 

 nical mixture, or a peculiar compound of iodine and the oil of cinnamon. This 

 action of water, however, is greatly diminished when it is close to the freezing 

 point, and appears altogether prevented when a certain amount of iodide of 

 potassium is present. 



When heated to 82° the crystals melt into a dark liquid, from which, upon 

 cooling, the original substance is reproduced. When heated beyond its melting 

 point, iodine and a vapour smelling strongly of oil of cinnamon, sublime, and 

 iodide of potassium is left behind, mixed usually with a little carbon, resulting 

 from the decomposition of a portion of the oil. Starch would appear to decom- 

 pose this substance, for with even its alcoholic or ethereal 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 ether may be 

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

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



