Iodine^ and the Essential Oil ofCinnamon» 117 



drawn out at the spirit lamp, it was hermetically sealed so as 

 effectually to prevent the volatilization of iodine. Agitation 

 was now resorted to, and a gentle heat at the same time ap- 

 plied, which caused the separation of the oil, the iodine pre- 

 viously combined with it having entered into union with the 

 zinc and formed with it a salt dissolved by the water. The tube 

 was now broken, and its contents having been thrown upon a 

 single filter previously deprived of all soluble matter, distilled 

 water was poured on until the entire quantity of the iodide of 

 zinc was carried through. The washings were concentrated, 

 suffered to cool, and then treated with the equivalent quantity 

 of nitrate of silver, and the resulting precipitate (iodide of 

 silver) having been, as in the previous experiment, sparingly 

 washed with cold water containing a little ammonia, was dried 

 and weighed. From this the total quantity of iodine in the 

 compound, both that combined with the potassium and with 

 the oil, was collected. But the quantity in the former state 

 having been already ascertained, the difference is the quantity 

 of iodine associated with the oil. 



In an experiment thus conducted 6'55 grains of the sub- 

 stance yielded of iodide of silver 4«'52 grains, equivalent to 

 37*20 grains of iodine for 100 of the compound. Subtracting 

 from this 9'58, the iodine of the iodide of potassium, we ob- 

 tain, as the representative of the amount of this element asso- 



28*66 + 27*62 



ciated with the oil, the number 27*62. Hence — 



2 



= 28*14 is the mean amount of the iodine in the latter state 



of combination as derivable from both experiments. But 



= 2*93, or 9*6 = 3. We thus arrive at the conclusion 



9*58 ' 



that for every atom of iodide of potassium in the substance 

 under consideration there are three atoms of iodine in combi- 

 nation with the oil of cinnamon. 



Before leaving this branch of the analysis, I may observe 

 that the iodine of the oil may be directly obtained by decom- 

 posing the compound in a glass tube at a red heat in contact 

 with lime, and acting upon the residue with water which dis- 

 solves the iodide of calcium, and along with it a little lime. 

 The latter being separated in the usual manner by carbonic 

 acid and boiling, the former may be precipitated by oxalate of 

 ammonia, and the iodine estimated from the amount of carbo- 

 nate of lime afforded by the oxalate when calcined at an ob- 

 scure red heat. 



The experiment made upon this plan did not give a very 

 satisfactory result; and, when I considered the great dispro- 



