Dr. Stenhouse'5 Examination ofCetine, Ethal, 8fc. 271 



tained in the liquid as protoxide (an addition of a ievf drops 

 of the sulphuretof ammonium answers the same purpose), and 

 then thrown down by cyanide of potassium, and an excess 

 of the latter added. The iron then dissolves immediately as 

 ferrocyanide of potassium, while the oxide of chromium is left 

 behind. In many cases the cyanide of potassium can be em- 

 ployed to advantage in separating iron from alumina (little 

 iron from much alumina), as the protoxide as well as the sul- 

 phuret of iron are so easily soluble in that salt, while alumina 

 is perfectly insoluble. The cyanide of potassium well deserves 

 to be studied as a general agent of separation. Unfortunately 

 the composition of the numerous double compounds it forms 

 with other cyanides is only imperfectly known, while their 

 relation to mineral and vegetable acids is wholly unknown, 

 so that the entire investigation must necessarily be repeated. 



XL. Examination of Cetine, Ethal, Oils of Laurel Tur- 

 pentine, Hi/ssop, and Assafoetida. By Dr. John Sten- 



HOUSE*. 



Cetine, 

 ^HEVREUL gave the name of Cetine to spermaceti when 

 ^^ rendered absolutely pure. The spermaceti of commerce 

 always contains more or less of a yellowish oil, which it re- 

 tains with great tenacity, and by which its melting point is 

 greatly lowered. The best means of purifying spermaceti, is 

 to tteat it two or three times with boiling alcohol, in which, 

 however, it is very slightly soluble, and then to subject it to 

 nine or ten crystallizations in {Ether. These solutions and 

 crystallizations must be repeated till the temperature at which 

 the cetine solidifies reaches \'2.0° F. or 121° F., when it may 

 be regarded as perfectly pure. 



The cetine which I subjected to analysis, was prepared in 

 the manner just described, and solidifies at 121° F. The 

 following are the results : — 



(1.) 0-236 gramme gave 0-6805 carbonic acid, and 0*2831 

 water. 



(2.) 0-3198 gramme gave 0*9223 carbonic acid, and 0-378 

 water. 



(3.) 0-2533 gramme gave 0-7286 carbonic acid, and 0-3008 

 water. 



(4.) 0*2928 gramme gave 0-84-68 carbonic acid, and 0-3476 

 water. 



• Communicated by the Chemical Society, having been read November 

 17tb, 1841. 



