1 18 Dr. Apjohn om a new Compound of Iodide of Potassium, 



portion between the atomic weights of iodine and of lime I did 

 not feel disposed to repeat the process. 



The iodine may also be taken out of the compound by filings 

 of iron as well as those of zinc, in the form of iodide of the 

 metal; and, though the theoretical objection just stated to the 

 process by lime is equally applicable to this method, a single 

 experiment, whose particulars I subjoin, thus conducted led 

 to a conclusion corresponding very closely with that already 

 obtained. 



8 grains of the compound gave 0*72 of peroxide of iron. 

 But this amount of peroxide corresponds to 2'27 of iodine. 

 Hence 



8 : 2'27 : : 100 : 28'41 - the 



percentage of iodine associated with the oil, and which ex- 

 ceeds the result, 28*14, obtained by the other methods by a 

 quantity so small that it may be viewed as affording a corro- 

 boration of the correctness of the previous determination. 



Having determined the iodide of potassium and the iodine 

 in union with the oil, we can now state the composition of the 

 compound, assuming the residue to be oil of cinnamon. 



Iodide of potassium 12*55 



Iodine 28-14 



Oil of cinnamon 59*30 



99-99 



That it is the oil itself, and no oxidized or other modifica- 

 tion of it, which exists in this compound, I have already as- 

 signed reasons for believing ; and as, by the application of 

 such heat as will fuse the compound, no water is set free, it 

 becomes highly probable that the statement above made is a 

 correct representation of its constitution. But the oil of cin- 

 namon has been analysed, and through the researches of Du- 

 mas we are acquainted with its real composition, which he has 

 shown to be represented by the formula C^g Hg O^. If then 

 the view numerically expressed above be the true one, the 

 59*30 parts of oil must correspond to some integer or at least 

 simple number of atoms. And, reciprocally, if we find such 

 to be the case, we shall be fortified in the conclusion which 

 we have drawn. 



With a view to this method of verification let the numbers 

 which represent the iodide of potassium and iodine, and that 

 which is supposed to represent the oil, be divided by their re- 

 spective atomic weights, and let the quotients be reduced to 

 others in the same ratio, nd so that the iodide of potassium 



